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Aberrant


Aberrant is an adjective pertaining to a deviation from normal.

Aberration


Aberration is the process of deviating from normal, a deviation.

Ablation


Ablation is the destruction of tissue, often by cautery, cryotherapy or laser.

Ablative


Ablative is an adjective pertaining to ablation, the destruction of tissue by laser, cautery, chemicals, surgery, or radiotherapy.

Abnormalities


Abnormalities: plural of abnormality; a noun for not normal things. Abnormalitites are uncharacteristic or unusual.

Abnormality


Abnormality is a noun for a not normal thing. An abnormality is something that is uncharacteristic or unusual.

Abscess


Abscess is a localised collection of pus.

Abscesses


Abscesses: plural of abscess; localised collections of pus.

Acantholysis


Acantholysis is a histological term for the separation of keratinocytes within the epidermis due to the loss of adhesion between keratinocytes.

Acantholytic


Acantholytic is an adjective used in histology to describe the loss of keratinocyte cohesion resulting in 'floating cells'.

Acanthoma


Acanthoma is a benign tumour located in the prickle cell layer of the epidermis. There are several specific forms of acanthoma.

Acanthosis


Acanthosis is a histological term for thickening of the epidermis and elongation of the rete ridges due to thickening of the spinous layer and enlargement of rete pegs.

Accentuate


Accentuate is a verb meaning to make more obvious or noticeable.

Accentuated


Accentuated pertains to the verb to accentuate; to make more obvious or noticeable.

Accentuation


Accentuation is the process of making more noticeable or obvious.

Achromia


Achromia means loss of colour. In the skin achromia is also called leukoderma or depigmentation, and means a lack or absence of melanin.

Acneform


Acneform is an adjective used to describe a resemblance to acne.

Acneiform


Acneiform is an adjective used to describe a resemblance to acne.

Acral


Acral is an adjective relating to or involving a distal site, eg, ear, finger, toe, nose, penis and nipple.

Acrochordon


Acrochordon is a fibroepithelial polyp of the skin, commonly known as a skin tag.

Acrochordons


Acrochordons: plural of acrochordon; fibroepithelial polyps of the skin, commonly known as skin tags.

Acrokeratoderma


Acrokeratoderma is skin thickening of the hands and feet, usually due to hyperkeratosis.

Actinic


Actinic is an adjective pertaining to sun or ultraviolet radiation.

Actinic keratoses


Actinic keratoses: plural of actinic keratosis; scaly skin spots with some keratinocyte atypia caused by chronic sun exposure.

Actinic keratosis


Actinic keratosis is a scaly skin spot showing some atypia of keratinocytes caused by chronic sun exposure.

Active substance


Active substance is an ingredient in a product that has the therapeutic effect.

Active substances


Active substances: plural of active substance; ingredients in a product that have the therapeutic effect.

Acuminate


Acuminate is an adjective used to describe a sharp and tapered point.

Acute


Acute is an adjective describing a sudden onset, sharp rise, or short course.

Adenocarcinoma


Adenocarcinoma: type of cancer derived from a mucin-producing gland.

Adenoma


Adenoma is a benign epithelial tumour with glands and gland-like structures.

Adenomas


Adenomas: plural of adenoma; benign epithelial tumours with glands or gland-like structures.

Adenomata


Adenomata: plural of adenoma; benign epithelial tumours with glands or gland-like structures.

Adenomatous


Adenomatous is an adjective used in histology to describe having glands and gland-like structures.

Adhesion


Adhesion is the process of the sticking together of components, eg, adhesion between keratinocytes.

Adipocyte


An adipocyte is a cell that stores fat. In the skin, adipocytes are located in subcutaneous tissue.

Adipocytes


Adipocytes are cells that store fat. In the skin, adipocytes are located in subcutaneous tissue.

Adipose


Adipose is fat.

Adipose cell


Adipose cell is a fat cell, also known as a lipocyte or adipocyte.

Adipose cells


Adipose cells: plural of adipose cell; fat cells, also known as lipocytes or adipocytes.

Adjacent


Adjacent is an adjective meaning to be next to or adjoining.

Adjunctive


Adjunctive is an adjective for additional, incidental, or subordinant.

Adjunctive therapy


Adjunctive therapy is an additional, often milder, treatment added to improve efficacy or safety of a therapeutic agent.

Adjuvant


Adjuvant is a noun and adjective meaning helper or helpful. An adjuvant is an extra agent added to improve efficacy, for example added to immunisations to improve the immune response. Adjuvant therapies are used after the main treatment for cancer to reduce the risk of recurrence and the chance of secondary tumours.

Adnexa


Adnexa is an accessory or appendage. In dermatology, an epidermal adnexa may be a hair, nail, or sweat gland.

Adnexae


Adnexae: plural of adnexa; appendages or accessories. In dermatology, the epidermal adnexae include hair follicles and sweat glands and ducts.

Adnexal


Adnexal is an adjective pertaining to an adnexa, an accessory or appendage. In dermatology, adnexal may pertain to hair, nail, sweat gland, etc.

Adrenaline


Adrenaline (American terminology epinephrine) is a hormone, neurotransmitter, and drug. The hormone is made in the adrenal gland and is involved in the fight-flight-fright reaction.

Adrenarche


Adrenarche is the increase in adrenal gland activity just before puberty.

Adverse drug reaction


Adverse drug reaction is an unexpected, sometimes harmful, event caused by a medication.

Adverse drug reactions


Adverse drug reactions: plural of adverse drug reaction; unexpected, sometimes harmful, events caused by a medication(s).

Adverse event


Adverse event is any untoward effect or episode occurring during treatment, but not necessarily due to that treatment.

Adverse events


Adverse events: plural of adverse event; any untoward effects or episodes occurring during treatment, but not necessarily due to that treatment.

Adverse reaction


Adverse reaction is an unexpected, sometimes harmful, event caused by a treatment or procedure.

Adverse reactions


Adverse reactions: plural of adverse reaction; unexpected, sometimes harmful, events caused by a treatment or procedure.

Adverse-drug reaction


Adverse-drug reaction is an unexpected, sometimes harmful, event caused by a medication.

Aeroallergen


Aeroallergen is an airborne substance that induces an allergic reaction. A common aeroallergen is pollen.

Aeroallergens


Aeroallergens: plural of aeroallergen; airborne substances that induce an allergic reaction. Common aeroallergens include pollen and fungal spores.

Aerobe


Aerobe is an organism that requires oxygen.

Aerobic


Aerobic is an adjective pertaining to an aerobe(s), a requirement for oxygen.

Aerosol foam


Aerosol foam is a solution with a pressurised propellant that emerges as a foam.

Aetiologies


Aetiologies: plural of aetiology (American spelling etiologies/etiology); causes of a situation such as a disease.

Aetiology


Aetiology (American spelling etiology) is the study of causes and causation. Aetiology is also the cause of a situation, eg, the aetiology of a disease may be an infection.

Aetiopathogenesis


Aetiopathogenesis means the cause and the subsequent development of a disorder.

Agglutination


Agglutination is the process of clumping. 

Agglutinin


Agglutinin is a molecule that binds to particles resulting in agglutination (clumping). An agglutinin is commonly an antibody (immunoglobulin) that may, for example, cause the clumping of red blood cells or pathogens.

Agglutinins


Agglutinins: plural of agglutinin; molecules that cause agglutination, the clumping together of particles such as red blood cells or pathogens.

Aggregate


Aggregate is a noun, verb, and adjective pertaining to collect, collection. For example, an aggregate of cells, and cells may aggregate together, to form an aggregate.

Aggregates


Aggregates: plural of aggregate (noun); collections; or the verb meaning to form a collection or cluster together.

Aggregation


Aggregation is a collection or clustering. For example, aspirin prevents platelet aggregation to form a clot.

Aggregations


Aggregations: plural of aggregation; collections or clusterings.

Agminated


Agminated is an adjective meaning clustered together.

Alanine aminotransferase


Alanine aminotransferase (acronym ALT), also known as alanine transaminase, is an enzyme measured in the blood to monitor liver damage due to medications, viral infections and other forms of inflammation.

Alanine aminotransferase (ALT)


Alanine aminotransferase, or ALT, is an enzyme present in the liver which is indicative of liver damage.

 

Alanine transaminase


Alanine transaminase (acronym ALT), also known as alanine aminotransferase, is an enzyme measured in the blood to monitor liver damage due to medications, viral infections, and other forms of inflammation.

Allele


Allele is a variant form of a gene found on the same locus of a chromosome.

Alleles


Alleles: plural of allele; variants of a gene found on the same locus of a chromosome.

Allergen


Allergen is a substance capable of inducing an immediate or delayed hypersensitivity reaction (allergy).

Allergenic


Allergenic is an adjective pertaining to the ability to induce an allergy.

Allergens


Allergens: plural of allergen; a chemical or substance capable of causing an allergic reaction.

Allergic reaction


Allergic reaction is a medical event due to an immunological response to an allergen. There are different types of allergic reaction classified by the immune mechanism.

Allergic reactions


Allergic reactions: plural of allergic reaction; medical events due to immunological responses to allergens. There are different types of allergic reactions classified by the immune mechanism.

Allergies


Allergies: plural of allergy; hypersensitivity reactions of various types; abnormal reactions of the immune system to exogenous agents.

Allergy


Allergy is a hypersensitivity reaction of which there are several different types; an abnormal reaction of the immune system to an exogenous agent such as pollen or peanuts.

Allodynia


Allodynia is a symptom, and describes when a non-painful stimulus, such as light touch, elicits severe pain, usually due to inflammation or change in nerve cells.

Alopecia


Alopecia is hair loss due to any cause. Alopecia can be diffuse or localised.

ALT


ALT is the acronym for alanine aminotransferase (alanine transaminase), an enzyme measured in the blood to monitor liver damage due to medications, viral infections, and other forms of inflammation.

Amblyopia


Amblyopia is dimness of vision due to abnormal development of the visual pathway. It results in a 'lazy eye' or 'wandering eye'. 

Amelanotic


Amelanotic is an adjective pertaining to a lack of melanin, the skin pigment.

Amenorrhea


Amenorrhea is the temporary or permanent absence of menstruation.

Amenorrhoea


Amenorrhoea (American spelling amenorrhea) is the temporary or permanent absence of menstruation.

Amino acid


Amino acid is the molecular building block of protein.

Amino acids


Amino acids: plural of amino acid; the molecular building blocks of proteins.

Amino-acid


An amino-acid is the building block of a protein. There are 20 amino acids. The essential amino acids are isoleucine, leucine, lysine, phenylalanine, threonine, tryptophan, and valine (essential because the human body cannot make them and must take them in the diet).

Aminoglycoside


Aminoglycoside is a class of antibiotic. An aminoglycoside inhibits bacterial protein synthesis, and is mainly used to treat Gram-negative infection.

Aminoglycosides


Aminoglycosides: plural of aminoglycoside; a class of antibiotics that inhibit bacterial protein synthesis, and are mainly used to treat Gram-negative infections.

Amniocentesis


Amniocentesis is a procedure to remove amniotic fluid from the pregnant uterus to screen for abnormalities in the fetus.

Amniotic


Amniotic is an adjective pertaining to the amnion, the membrane that encloses an embryo/fetus during pregnancy.

Amorphous


Amorphous is an adjective describing a lack of form or shape.

Amphiphilic


Amphiphilic is an adjective describing the ability to combine with or dissolve in both lipids and water.

Amyloid


Amyloid is an abnormal aggregate of proteins deposited in tissue with characterstic staining and appearance on microscopy.

Amyloidosis


Amyloidosis is a disorder characterised by the formation and deposition of amyloid.

Anaemia


Anaemia (American spelling anemia) is an abnormal low haemoglobin content or number of peripheral red blood cells.

Anaemic


Anaemic is an adjective pertaining to anaemia, a low haemoglobin content or number of red blood cells.

Anaerobe


Anaerobe is an organism that does not require oxygen. It may be a facultative anaerobe meaning it tolerates oxygen in its environment, or a strict anaerobe meaning it is killed by oxygen.

Anaerobes


Anaerobes: plural of anaerobe; organisms that do not require oxygen.

Anaerobic


Anaerobic is an adjective pertaining to not requiring or wanting free oxygen.

Anaesthesia


Anaesthesia (American spelling anesthesia) is a state of chemically induced insensitivity or insensibility. Anaesthesia can be general, when the patient is rendered unconscious; or local, when only a part of a tissue is numb.

Anaesthetic


Anaesthetic (American spelling anesthetic) is an adjective pertaining to anaesthesia, a loss of sensation or sensibility. Common usage also makes anaesthetic a noun meaning a drug used to reduce sensation or consciousness.

Anaesthetist


Anaesthetist (American terminology anesthesiologist) is a medical specialist in the area of anaesthesia. Most commonly anaesthetists administer and monitor general and regional anaesthesics.

Anagen


Anagen is the growth phase of the hair follicle.

Anal


Anal is an adjective pertaining to the anus, the opening at the end of the bowel through which faeces exit the body.

Analgesia


Analgesia is a pain relieving medication.

Analogue


Analogue is something similar that can often be substituted, eg, a drug may be an analogue of another if it has a similar structure and action.

Analogues


Analogues: plural of analogue; similar things, eg, drugs may be analogues if they have similar structures and actions.

Anaphylactic


Anaphylactic is an adjective pertaining to anaphylaxis, an immediate hypersensitivity reaction.

Anaphylactoid


Anaphylactoid is an adjective meaning to resemble anaphylaxis, an immediate hypersensitivity reaction.

Anaphylaxis


Anaphylaxis is an immediate hypersensitivy reaction that can be severe, and potentially fatal, in a sensitised individual.

Anaplastic


Anaplastic is an adjective used in histology to describe specific features usually indicative of malignancy. Anaplastic cells have irregular dark-staining nuclei, and are typically poorly differentiated.

Anatomical region


Anatomical region is one area of the body. Examples the head and neck; trunk; upper or lower limb.

ANCA


ANCA is the acronym for antineutrophil cytoplasmic antibody. Indirect immunofluorescence of neutrophils classifies ANCA into several types: cytoplasmic ANCA (c-ANCA) targets proteinase-3 in the cytoplasm of monocytes and neutrophils: perinuclear ANCA (p-ANCA) targets myeloperoxidase in granules of myelocytes, promyelocytes and neutrophils: atypical ANCA (x-ANCA).

Androgen


Androgen is a class of steroid hormone responsible for the development of male characteristics.

Androgenetic


Androgenetic is an adjective pertaining to a genetic (familial) susceptibility to androgens, the male hormones. It is typically used to describe a form of patterned hair loss, androgenetic alopecia.

Androgens


Androgens: plural of androgen; steroid hormones responsible for the development of male characteristics.

Aneurysm


Aneurysm: a bulging outwards from a weak point in a blood vessel wall

Angina


Angina is a chocking suffocating feeling in the throat.

Angioedema


Angioedema describes rapid and temporary swelling deep in the skin or mucous membranes.

Angioendotheliosis


Angioendotheliosis: proliferation of endothelial cells within blood vessels.

Angiofibroma


Angiofibroma is a family of benign (non-cancerous) tumours composed of increased dermal fibroblasts in a collagenous stroma, and numerous dilated dermal blood vessels.

Angiofibromas


Angiofibromas: plural of angiofibroma; benign tumours composed of increased dermal fibroblasts in a collagenous stroma, and numerous dilated dermal blood vessels.

Angiogenesis


Angiogenesis is the formation of new blood vessels.

Angiogenic


Angiogenic is an adjective pertaining to angiogenesis, the formation of new blood vessels.

Angiogram


Angiogram is a radiograph that displays blood vessels or lymphatic vessels.

Angiography


Angiography is the radiological process to display blood vessels or lymphatic vessels.

Angiokeratoma


Angiokeratoma is a capillary vascular malformation composed of epidermal hyperkeratosis overlying a cluster of dilated upper dermal capillaries.

Angiokeratomas


Angiokeratomas: plural of angiokeratoma; capillary vascular malformations composed of epidermal hyperkeratosis overlying a cluster of dilated upper dermal capillaries.

Angiolipoma


Angiolipoma is a benign encapsulated tumour composed of fat lobules and numerous capillaries. It may be infiltrating or non-infiltrating, solitary or multiple, painful or asymptomatic.

Angiolipomas


Angiolipomas: plural of angiolipoma; benign encapsulated tumours composed of fat lobules and numerous capillaries.

Angioma


Angioma is a benign collection of dilated congested blood vessels. On the skin an angioma typically presents as a red papule. The cherry angioma is a common example.

Angiomas


Angiomas: plural of angioma; benign collections of dilated congested blood vessels. Cherry angiomas are commonly seen on the skin.

Angiomatosis


Angiomatosis is a group of conditions characterised by vascular malformations or angiomas.

Angiomyxoma


Angiomyxoma, also called a myxoma, is an acquired benign neoplasm composed of a mucinous matrix and prominent dilated capillaries. An angiomyxoma may be solitary or one of many.

Angiomyxomas


Angiomyxomas: plural of angiomyxoma; also called myxomas; acquired benign neoplasms composed of a mucinous matrix and prominent dilated capillaries.

Angiotropic


Angiotropic is an adjective to describe having an affinity for, or moving towards, blood vessels, eg, angiotropic large cell lymphoma.

Anhidrosis


Anhidrosis is the inability to sweat appropriately; it may be due to an abnormaiity of the sweat glands or associated with a neurological lesion or disease.

Annular


Annular is an adjective describing a ring-like or circular shape. In dermatology this may be used for lesions grouped in a circle, or a ring-shaped lesion as in granuloma annulare.

Anogenital


Anogenital is the adjective pertaining to the area around the anus and genitals.

Anorectal


Anorectal is an adjective pertaining to the rectum, the final section of the bowel, and anus, the opening to the outside through which faeces exit the body.

Antenatal


Antenatal, or prenatal, is an adjective meaning before birth, eg, antenatal checkup.

Anterior


Anterior is an adjective to describe being towards the front or before. In anatomy, anterior location means on the front (ventral) surface of a body part, eg, the anterior eye meaning the front of the eye.

Anti-inflammatories


Anti-inflammatories: plural of anti-inflammatory; drugs used to treat or prevent inflammation.

Anti-inflammatory


Anti-inflammatory is an adjective used to describe reducing or combating inflammation, eg, an anti-inflammatory drug. Common usage is as a noun, ie, an anti-inflammatory (drug).

Anti-neoplastic


Anti-neoplastic (antineoplastic) is an adjective used to describe a process or agent that inhibits the proliferation of tumour cells.

Antibodies


Antibodies: plural of antibody; immunoglobulin proteins produced by plasma cells directed against specific antigens including infections and toxins.

Antibody


Antibody (acronym Ab) is an immunoglobulin, a protein produced by plasma cells directed against a specific antigen including infections and toxins.

Anticonvulsant


Anticonvulsant is an adjective and noun pertaining to the prevention of convulsions, typically used to describe a family of drugs for the treatment of epilepsy. Common usage makes it a noun, ie, an anticonvulsant (drug).

Anticonvulsants


Anticonvulsants: plural of anticonvulsant; drugs that prevent convulsions, typically used to treat epilepsy.

Antigen


Antigen (acronym Ag) is any substance that evokes an immediate or delayed immune response.

Antigen receptor


Antigen receptor is a membrane-bound immunoglobulin protein on the surface of an immune cell that recognises and binds to a specific antigen.

Antigen receptors


Antigen receptors: plural of antigen receptor; membrane-bound immunoglobulin proteins on the surfaces of immune cells that recognise and bind antigens.

Antigenic


Antigenic is an adjective pertaining to an antigen(s), a chemical that evokes an immediate or delayed hypersensitivity reaction.

Antigens


Antigens: plural of antigen; substances that evoke an immediate or delayed immune response.

Antimicrobial


Antimicrobial is an adjective that means being against a microbe; it describes the action of killing or slowing the growth of microorganisms such as bacteria, viruses, or fungi. Common usage also makes antimicrobial a noun, ie, an antimicrobial (drug).

Antimicrobials


Antimicrobials: plural of antimicrobial; agents that kill or slow the growth of microorganisms such as bacteria, viruses, or fungi.

Antineoplastic


Antineoplastic is an adjective used to describe a process or agent that inhibits the proliferation of tumour cells.

Antineutrophil cytoplasmic antibodies


Antineutrophil cytoplasmic antibodies: plural of antineutrophil cytoplasmic antibody (acronym ANCA). Indirect immunofluorescence of neutrophils classifies ANCA into several types: cytoplasmic ANCA (c-ANCA) targets proteinase-3 in the cytoplasm of monocytes and neutrophils; perinuclear ANCA (p-ANCA) targets myeloperoxidase in granules of myelocytes, promyelocytes and neutrophils; atypical ANCA (x-ANCA).

Antiproliferative


Antiproliferative is an adjective used to describe a process or agent that reduces the ability of cells to replicate, eg, antiproliferative drugs may be used to treat cancer.

Antiviral


Antiviral is an adjective to describe being against viruses, eg, an antiviral drug. Common usage also makes antiviral into a noun, ie, an antiviral (agent).

Anus


Anus is the opening at the end of the bowel, through which faeces exit the body.

Aortic


Aortic is an adjective pertaining to the aorta, the very large artery in the chest and abdomen that leads away from the heart.

Aplasia


Aplasia is the failure to develop, as in aplasia cutis.

Aplastic/aplasia


Aplastic refers to incomplete or defective development of an organ. It is often used to refer to absence of blood cells in aplastic anaemia.

Apocrine


Apocrine is an adjective pertaining to glands that form a secretion by releasing cytoplasm.

Apocrine gland


Apocrine gland is a scent gland mostly found in the armpits and groin which becomes active after puberty.

Apocrine glands


Apocrine glands: plural of apocrine gland; scent glands mostly found in armpits and groin which become active after puberty. Apocrine sweat is oily, thick and odourless; the smell derives from bacterial decomposition.

Apoplexy


Apoplexy comes from the Greek to mean a seizure or striking down. In medicine it was used for bleeding into an organ, but now is rarely used except to describe bleeding into the pituitary gland (pituitary apoplexy).

Apoptosis


Apoptosis is the regulated, normal physiological process by which a cell undergoes self destruction in response to signals from the cell nucleus.

Apoptotic


Apoptotic is an adjective pertaining to apoptosis, the normal process by which a cell undergoes self-destruction.

Appendage


Appendage is an additional thing or supplement.

Appendages


Appendages: plural of appendage; additional things or supplements. The skinl appendages are things additional to the epidermis and include eccrine (sweat) glands, apocrine (scent) glands, pilosebaceous structures (hair and oil glands) and nails.

Aquagenic


Aquagenic is an adjective pertaining to being caused by water, usually due to contact with water.

Arachnid


Arachnid is an arthropod with four pairs of legs, eg, spider, mite.

Arachnids


Arachnids: plural of arachnid; arthropods with four pairs of legs, eg, spiders, mites.

Arborising


Arborising (arborizing) means treelike branching.

Arciform


Arciform is an adjective to describe an arched or bow shape.

Arcuate


Arcuate is an adjective to describe an arched or bow-shape.

Areola


Areola is a circular area. In anatomy the areola is the pigmented circular area around the breast nipple. It is also used in dermatology to mean a red ring around an inflamed spot.

Areolae


Areolae: plural of areola; circular areas. In anatomy the areolae are the pigmented circular areas around the breast nipples. Areolae is also used in dermatology to mean red rings around inflammed spots.

Areolar


Areolar is an adjective pertaining to areola, the pigmented area around the breast nipple.

Array


Array is a large group arranged or organised in columns and rows.

Arrays


Arrays: plural of array; large groups arranged or organised in columns and rows.

Arrector pili muscle


Arrector pili muscle is the small muscle which originates near the basement-membrane zone and attaches to the hair follicle. Contraction of an arrector pili muscle causes the erection of the hair on exposure to cold or fear, to produce a goose-bump.

Arrector pili muscles


Arrector pili muscles: plural of arrector pili muscle; small muscles which originate near the basement-membrane zone and attach to the hair follicles. Contraction of arrector pili muscles causes the erection of hairs on exposure to cold or fear to produce goose bumps.

Arrhythmia


Arrhythmia means a lack or absence of rhythm. A cardiac arrhythmia is an abnormal or irregular heart beat.

Arrhythmias


Arrhythmias: plural of arrhythmia; cardiac arrhythmias are abnormal or irregular heart beats.

Artefact


Artefact: a skin lesion produced by a self-inflicted action.

Arterial


Arterial is an adjective pertaining to an artery/arteries, the muscular blood vessels taking blood away from the heart.

Arteries


Arteries: plural of artery; the muscular blood vessels that carry blood away from the heart.

Arteriole


Arteriole is a very small terminal end of an artery that connects the arterial system to a capillary.

Arterioles


Arterioles: plural of arteriole; very small terminal ends of arteries that connect the arterial system to capillaries.

Arteriosclerosis


Arteriosclerosis, also known as atherosclerosis, is a disease of the arteries in which plaques of fat, cholesterol and calcium form in the vessel wall causing narrowing of the artery lumen.

Arteritis


Arteritis is inflammation of an artery/arteries.

Artery


Artery is a muscular blood vessel that carries blood away from the heart.

Arthralgia


Arthralgia is joint pain without swelling.

Arthralgias


Arthralgias: plural of arthralgia; pain without swelling in joints.

Arthritis


Arthritis is inflammation of a joint(s).

Arthropathic


Arthropathic is an adjective pertaining to an arthropathy, a joint disease.

Arthropathies


Arthropathies: plural of arthropathy; diseases of the joints.

Arthropathy


Arthropathy is any joint disease.

Arthropod


Arthropod is an invertebrate animal with a segmented body, jointed limbs, and a hard shell that is shed periodically.Examples of an arthropod include an insect, spider, and crustacean.

Arthropods


Arthropods: plural of arthropod; invertebrate animals with a segmented body, jointed limbs, and a hard shell that is shed periodically. Insects, spiders, and crustacea are examples of arthropods.

Ascites


Ascites is the abnormal accumulation of fluid in the peritoneal cavity of the abdomen.

Aspartate aminotransferase


Aspartate aminotransferase (acronym AST), also called aspartate transaminase, is an enzyme that can be measured in the blood to detect tissue damage caused by medications, viral infections, or other inflammation. It is found in liver, heart, skeletal muscles, and other tissues.

Aspartate transaminase


Aspartate transaminase (acronym AST), also called aspartate aminotransferase, is an enzyme that can be measured in the blood to detect tissue damage caused by medications, viral infections, or other inflammation. It is found in liver, heart, skeletal muscles, and other tissues.

Asphyxiated


Asphyxiated derives from the verb to asphyxiate, to cause death of an organism by obstructing breathing resulting in a lack of oxygen to tissues.

Asphyxiating


Asphyxiating derives from the verb to asphyxiate, to obstruct breathing and cause death of an organism due to lack of oxygen.

Asphyxiation


Asphyxiation is the process by which the death of an organism is due to lack of tissue oxygen usually caused by obstructed breathing (asphyxia).

Aspirate


Aspirate is the verb to breathe in or out fluid or solid matter into or out from the airways.

Aspirated


Aspirated is a verb and adjective related to aspiration, the breathing in or out of fluids or solid material into or out from the airways, eg, the patient has aspirated vomit, there is an aspirated foreign body.

Aspiration


Aspiration is the process of sucking in and out through the airways. Aspiration-in usually means the breathing in of material foreign to the airways including vomit and foreign bodies. Aspiration-out is the medical procedure to suck out material from the airways including excessive mucus that cannot be coughed up and out.

AST


AST is the acronym for aspartate transaminase and aspartate aminotransferase. AST is an enzyme that can be measured in the blood to detect tissue damage caused by medications, viral infections or other inflammation. It is found in liver, heart, skeletal muscles, and other tissues.

Astigmatism


Astigmatism means there is an irregularity in the curvature of the eyeball resulting in blurry vision.

Asymmetrical


Asymmetrical is an adjective pertaining to a lack of symmetry along an axis. In dermatology asymmetrical may be used to describe the shape of a lesion or the distribution pattern of a rash.

Asymptomatic


Asymptomatic is an adjective to describe the absence of symptoms.

Atherosclerosis


Atherosclerosis, also known as arteriosclerosis, is a disease of the arteries in which plaques of fat, cholesterol and calcium form in the vessel wall causing narrowing of the artery lumen.

Atherosclerotic


Atherosclerotic is an adjective pertaining to atherosclerosis; arteries narrowed by plaque deposition.

Atopic


Atopic is an adjective pertaining to atopy, an inherited tendency to develop allergies such as hay fever (allergic rhinitis), asthma, food allergies, and atopic dermatitis.

Atopy


Atopy is a genetic (inherited) tendency to develop allergies such as hay fever (allergic rhinitis), asthma, food allergies, and atopic dermatitis.

Atrichia


Atrichia is the absence of hair which can be either congenital or acquired.

Atrophic


Atrophic is an adjective pertaining to atrophy, the loss of tissue.

Atrophie blanche


Atrophie blanche is a white atrophic scar typically seen in livedoid vasculopathy.

Atrophoderma


Atrophoderma is a group of conditions characterised by thinning of the dermis; dermal atrophy. There are specific forms of atrophoderma.

Atrophy


Atrophy is the loss or shrinkage of a component of a tissue after having developed normally. In the skin, the epidermis, dermis or subcutaneous fat may show atrophy.

Attenuated


Attenuated is an adjective meaning to be weaker.

Atypia


Atypia is a histological term to indicate variations from normal. Cellular atypia can be malignant or benign. Architectural atypia means an abnormal arrangement.

Atypical


Atypical is an adjective pertaining to atypia, not typical. In dermatology, it may be used to describe unusual-looking lesions such as atypical moles.

Augmentation


Augmentation means enhancement, enlargement, or increased. In dermatology, augmentation may include the injection of fillers into scars and wrinkles.

Auricle


Auricle is the visible part of the ear and the upper part of the heart which is ear-shaped.

Autoamputation


Autoamputation is the spontaneous detachment of an appendage, such as a toe, from the body. This may be due to constriction from a fibrous band or other causes of prolonged ischaemia and tissue necrosis.

Autoantibodies


Autoantibodies: plural of autoantibody; immunoglobulins directed against normal components of the host individual producing them (self, auto).

Autoantibody


Autoantibody is an immunoglobulin directed against a normal component of the host individual producing it (self, auto).

Autoantigen


Autoantigen is a normal self-protein targeted by a host antibody.

Autoantigens


Autoantigens: plural of autoantigen; normal self-proteins targeted by host antibodies.

Autoimmune


Autoimmune is an adjective to describe antibodies directed against a normal host antigen.

Autoimmunity


Autoimmunity is an immune reaction against 'self'; when antibodies are made against a normal body protein resulting in disease.

Autoinflammatory


Autoinflammatory is an adjective describing recurrent inflammatory episodes not associated with an autoimmune disease, malignancy, allergy, immunodeficiency or infection.

Autoinoculation


Autoinoculation is self-inoculation; the spread of infection from one body site to another. In the skin, autoinoculation commonly occurs by scratching or touching an infected site then transferring the infection to another area via the contaminated finger.

Autonomic


Autonomic is an adjective pertaining to being involuntary.

Autonomic nervous system


Autonomic nervous system controls involuntary actions such as the contraction of the heart and secretion from glands.

Autopsy


Autopsy, also called post-mortem examination, is the examination of a body after death, usually performed to determine the cause of death.

Autosomal


Autosomal is an adjective pertaining to a non-sex chromosome. It is usually used in the context of a genetically inherited condition, eg, an autosomal dominant or autosomal recessive condition.

Autosomal dominant


Autosomal dominant is an adjective to describe a genetic disorder in which only one copy of the abnormal gene is required to cause the condition, and that gene is located on a non-sex chromosome.

Autosomal dominant inheritance


Autosomal dominant inheritance is where the inheritance of a characteristic or disease requires only one copy of the mutated gene for expression, and that gene is located on a non-sex chromosome.

Autosomal recessive


Autosomal recessive is an adjective to define a genetic disorder that requires both copies of a gene to be abnormal to cause the condition, and that gene is located on a non-sex chromosome.

Autosomal recessive inheritance


Autosomal recessive inheritance is the inheritance of a characteristic or disease requiring both copies of the gene to be abnormal, and that gene is located on a non-sex chromosome.

Autosomal-dominant


Autosomal-dominant is an adjective to describe a genetic characteristic or disease that requires only one copy of the mutated gene for expression, and that gene is located on a non-sex chromosome.

Autosomal-dominant inheritance


Autosomal-dominant inheritance is where the inheritance of a characteristic or disease requires only one copy of the mutated gene for expression, and that gene is located on a non-sex chromosome.

Autosomal-recessive


Autosomal-recessive is a term used in genetics for a condition that requires both copies of a gene on a non-sex chromosome to be mutated.

Autosomal-recessive inheritance


Autosomal-recessive inheritance is the inheritance of a characteristic or disease requiring both copies of the gene on a non-sex chromosome to be mutated.

Averse reaction


An adverse reaction is a harmful event caused by a medication or procedure.

Axial


Axial is an adjective pertaining to the axis, the centre or midline of a body about which it rotates; thus the axial skeleton is the cranium, sternum and spine.

Axilla


Axilla is the armpit.

Axillae


Axillae: plural of axilla; armpits.

Axon


Axon is a long thread-like extension (dendrite) of a nerve cell (neurone) along which electrical impulses are conducted.

Axons


Axons: plural of axon; dendrites of nerve cells (neurones) along which electrical impulses are conducted.

Azoospermia


Azoospermia is the state of having no live sperm in the semen.

B


B cell


B cell, also called a B lymphocyte, originates in the bone marrow and is normally involved in producing immunoglobulins to detect and combat infection. An activated antibody-producing B cell is called a plasma cell.

B cells


B cells: plural of B cell; also called B lymphocytes; originate in the bone marrow and are normally involved in the production of immunoglobulins to detect and combat infection.

B lymphocyte


B lymphocyte, also called a B cell, originates in the bone marrow and is normally involved in producing immunoglobulins to detect and combat infection.

B lymphocytes


B lymphocytes: plural of B lymphocyte; also called B cells; bone marrow-derived cells involved in the production of immunoglobulins.

Bacteraemia


Bacteraemia (American spelling bacteremia) is the presence of bacteria in the blood.

Bacteria


Bacteria: plural of bacterium; single-celled prokaryotic micro-organisms that lack a nucleus. Bacteria can live in the environment, on plants and animals, including humans where they may be commensal, harmless, or disease-causing.

Bacterial


Bacterial is an adjective pertaining to bacteria, single-celled prokaryotic micro-organisms.

Bactericidal


Bactericidal is an adjective pertaining to the killing of bacteria.

Bacterium


Bacterium is a single-celled prokaryotic micro-organism that lacks a nucleus. It may be aerobic or anaerobic; environmental or associated with plants or animals; pathogenic or harmless, foreign or commensal.

Balanitis


Balanitis is the inflammation of the glans (head) of the penis.

Basal


Basal is an adjective pertaining to a base, the bottom-most layer.

Basal layer


Basal layer is the bottom-most layer. In the epidermis and mucous membranes the basal layer is called the stratum basale and sits immediately above the basement-membrane zone. It is composed predominantly of columnar or rectangular cells from which new keratinocytes are continuously produced. Scattered melanocytes are also normally found in this layer.

Basalioma


Basalioma is another name for basal cell carcinoma, the commonest form of skin cancer.

Basaliomas


Basaliomas: plural of basalioma; another name for basal cell carcinomas.

Basaloid


Basaloid is an adjective used in histology to describe resembling epidermal basal cells.

Baseline


Baseline is a starting point, a term used in sport and in medicine. In medicine it may be used to define the point before an illness began or before a treatment started.

Basement membrane


Basement membrane is the structure between an epithelium (epidermis in skin) and the underlying connective tissue (dermis in skin).

Basement membrane zone


Basement membrane zone is a thin, non-cellular layer between the epidermis and dermis, composed of various protein structures linking the basal layer of keratinocytes to the basement membrane (hemidesmosomes), and the basement membrane to the underlying dermis (anchoring fibrils). The basement membrane zone has an important role in making sure the epidermis remains attached to the underlying dermis.

Basement-membrane zone


Basement-membrane zone is a thin, non-cellular layer between the epidermis and dermis, composed of various protein structures linking the basal layer of keratinocytes to the basement membrane (hemidesmosomes), and the basement membrane to the underlying dermis (anchoring fibrils). The basement-membrane zone has an important role in making sure the epidermis remains attached to the underlying dermis.

Basophil


Basophil is a granulocytic white blood cell (leukocyte) closely related to mast cells and eosinophils and involved in allergic disease. The cytoplasm of a basophil contains granules that stain blue with basic dyes, ie, basophilic.

Basophilic


Basophilic is an adjective pertaining to staining with basic dyes. Examples in dermatology include the basophilic cytoplasm of plasma cells, basophilic cells of the epidermal basal layer, and basophilic granules in some blood leukocytes.

Basophils


Basophils: plural of basophil; granulocytic white blood cells (leukocytes) closely related to mast cells and eosinophils and involved in allergic disease. The cytoplasm of basophils contains granules that stain blue with basic dyes.

Beau line


Beau line is a transverse depression affecting a nail, due to acute systemic illness stopping nail growth.

Beau lines


Beau lines: plural of Beau line; transverse depressions affecting nails, due to acute systemic illness stopping nail growth.

Benign


Benign is an adjective to describe being mild, harmless, non-cancerous, or having a good prognosis.

Benign keratoses


Benign keratoses: plural of benign keratosis; a general term covering seborrhoeic keratoses, solar lentigines, lichen planus-like keratoses or a combination of these lesions.

Benign keratosis


Benign keratosis is a term used in clinical dermatology and specifically reflectance confocal microscopy to describe the features seen on examination of a solar lentigo, a seborrhoeic keratosis, a lichen planus-like keratosis or a combination of these.

Bilateral


Bilateral is an adjective describing involvement of two sides but does not imply symmetry. Bilateral skin disorders affect both sides of the body.

Biliary


Biliary is an adjective pertaining to bile produced in the liver, stored in the gallbladder, and transported along the bile duct to the duodenum to aid in digestion.

Bilirubin


Bilirubin is a yellow pigment produced in the liver by the degradation of haem.

Binocular


Binocular is an adjective describing the use or involvement of two eyes, eg, binocular vision.

Bioavailability


Bioavailability: the amount of a drug entering into the systemic circulation.

Biocide


A substance or microorganism intended to destroy, deter, disable, or control a harmful organism, eg, disinfectant, preservative, insecticide.

Biofilm


Biofilm is a thin layer of bacteria and secreted polymers adhering to the surface of a structure. A biofilm can form on organic surfaces, such as skin or teeth, or inorganic structures, such as tubes or catheters.

Biomarker


Biomarker is a naturally occurring molecule, gene, or characteristic by which a particular pathological or physiological process, disease, etc. can be identified.

Biomarkers


Biomarkers: plural of biomarker; naturally occurring molecules, genes, or characteristics by which a particular pathological or physiological process, disease, etc. can be identified.

Biopolymer


Biopolymer is a polymer (chain of molecules) in living tissue and cells. There are three classes of biopolymer: polymers of nucleotides (DNA or RNA), polymers of amino acids (peptides or proteins), and polymers of carbohydrates (polysaccharides).

Biopolymers


Biopolymers: plural of biopolymer; polymers (chains of molecules) in living tissues and cells.

Biopsies


Biopsies: plural of biopsy (noun); tissue samples. Biopsies is also a verb meaning the obtaining of a tissue sample, eg, the dermatologist biopsies the skin.

Biopsy


Biopsy is a noun and verb pertaining to a tissue sample, eg, a dermatologist may take a skin biopsy, the dermatologist may biopsy the skin.

Blanch


Blanch is a verb meaning to whiten or make pale, eg to blanch with fear or to blanch vegetables. In dermatology it is used to describe the removal of normal skin colour, erythema or telangiectasis by pressure, indicating the colour is due to blood in dilated surface capillaries and small blood vessels.

Blanching


Blanching is an adjective, verb and noun pertaining to blanch, pallor, paleness, whiteness. In dermatology a blanching rash or lesion is describing the loss of colour, erythema or telangiectasis by pressure, blanching the vegetables, blanching occured.

Blaschko line


Blaschko line is an embryological clonal expansion line in the skin following a roughly linear, segmental pattern. A birthmark may be distributed along a Blaschko line.

Blaschko lines


Blaschko lines: plural of Blaschko line; embryological clonal expansion lines in the skin following a roughly linear, segmental pattern. Many birthmarks appear to be distributed along these lines.

Bleb


Bleb is a small thin-walled blister containing air or fluid.

Blebs


Blebs: plural of bleb; small thin-walled blisters containing fluid or air.

Blepharoconjunctivitis


Blepharoconjunctivitis is inflammation of the eyelids and conjunctiva at the same time.

Blood vessel


Blood vessel is a tube to carry blood around the body. Examples include an artery, arteriole, capillary, venule, or vein.

Blood vessels


Blood vessels: plural of blood vessel; tubular structures including arteries, arterioles, capillaries, venules, and veins, that carry blood around the body.

Brachy-


Brachy- is a prefix meaning short, as in brachyonychia to mean a short nail.

Bradycardia


Bradycardia is an abnormally slow heart rate of less than 60 beats per minute.

Bradykinin


Bradykinin is a naturally occurring peptide in the body involved in inflammation including the innate immune system. It causes smooth muscle relaxation in arteries (vasodilation), but constriction in the gut and respiratory tree. Bradykinin also increases vascular permeability and has a diuretic effect.

BRAF


BRAF is a proto-oncogene that encodes a threonine protein kinase called B-Raf. It is essential for normal cell development and function however mutations in the BRAF gene may result in cancer.

BRAF inhibitor


BRAF inhibitor is a drug that directly targets a mutated BRAF protein to shrink or slow the growth of a tumour.

BRAF inhibitors


BRAF inhibitors: plural of BRAF inhibitor; drugs that directly target a mutated BRAF protein to shrink or slow the growth of a tumour.

Breslow thickness


Breslow thickness, also called Breslow depth, is the thickness of an invasive melanoma in millimetres measured from the granular cell layer to the deepest tumour cell. Breslow thickness is an important prognostic factor so should be measured and recorded on the histology report.

Bromhidrosis


Bromhidrosis is an abnormal or offensive body odour.

Bronchiolitis obliterans


Bronchiolitis obliterans: an inflammatory fibroproliferative disease affecting the bronchioles, causing fibrosis (scarring) and progressive, largely irreversible, lung damage

Bronchospasm


Bronchospasm is the tightening of the respiratory muscles leading to wheeze.

Buccal


Buccal: is an adjective pertaining to the cheek.

Bull's eye


Bull's eye is an adjective or noun pertaining to concentric rings or target. In dermatology, target or iris lesions have a bull's eye appearance.

Bull's-eye


Bull's-eye is an adjective and noun pertaining to concentric rings as in a target. In dermatology, a bull's-eye appearance describes an iris lesion or target lesion.

Bulla


Bulla is a large blister, more than 1 cm in diameter, and containing clear, serous, or haemorrhagic fluid. A skin bulla may be within the epidermis (intraepidermal) or below the basement membrane (subepidermal).

Bullae


Bullae: plural of bulla; large fluid-filled blisters, greater than 1 cm in diameter.

Bullous


Bullous is an adjective pertaining to bulla(e), large blister(s).

Bulls-eye


Bulls-eye is an adjective and noun pertaining to concentric rings as in a target. In dermatology, a bulls-eye appearance describes an iris lesion or target lesion.

Burrow


Burrow is a hole or tunnel. In dermatology, a burrow may be due to a tunneling parasite such as the scabies mite and others.

Burrows


Burrows: plural of burrow; holes or tunnels.

C


C-reactive protein


C-reactive protein (acronym CRP) is a nonspecific inflammatory marker protein produced by the liver and commonly measured in the blood. An elevated CRP in the blood is associated with infection, tumours and inflammatory diseases.

Cachectic


Cachetic is an adjective pertaining to cachexia, a state of weight loss and poor quality of life associated with cancer, AIDS, and chronic organ failure.

Cachexia


Cachexia is a state of weight loss associated with anorexia, muscle and fat loss, poor quality of life, and fatigue. It is associated with cancer, AIDS, and chronic organ failure such as congestive cardiac failure or renal failure.

Calcification


Calcification is the process of depositing calcium salts in body tissues.

Calvaria


Calvaria, also called calvarium, is the top of the skull.

Calvarium


Calvarium, also called calvaria, is the top of the skull.

Cancer


Cancer is a generic term for a malignant tumour, in which there is uncontrolled clonal cell proliferation and destruction of local tissue, with the potential to spread to distant sites (metastasise).

Capillaries


Capillaries: plural of capillary; very small thinwalled vessels which, in the body, connect the arterial and venous systems.

Capillary


Capillary is a noun and adjective pertaining to being fine, filamentous and hair-like. In the body a capillary is a very small blood vessel connecting between the arterial and venous systems; a capillary tube or capillary action; being related to the vascular capillaries, eg, a capillary bed.

Carbohydrate


Carbohydrate is a chemical compound made up of carbon (carbo), hydrogen (hydr), and oxygen (ate), used as a major source of stored energy in the body.

Carbohydrates


Carbohydrates: plural of carbohydrate; chemical compounds made up of carbon, hydrogen, and oxygen, used as a major source of stored energy in the body.

Carcinogen


Carcinogen is an agent or substance that promotes, causes, or increases the risk of cancer.

Carcinogenic


Carcinogenic is an adjective pertaining to the triggering of cancer development.

Carcinogens


Carcinogens: plural of carcinogen; substances or agents that promote, cause, or increase the risk of cancer.

Carcinoma


Carcinoma is a malignant tumour of epithelial cells. The two most common forms of skin carcinoma are basal cell carcinoma and squamous cell carcinoma.

Carcinomas


Carcinomas: plural of carcinoma; malignant tumours of epithelial cells. The two most common skin carcinomas are basal cell carcinomas and squamous cell carcinomas.

Cardiomyopathy


Cardiomyopathy is any disease of the heart muscle.

Carotenaemia


Carotenaemia (American spelling carotenemia) is elevated beta-carotene level in the blood due to the excessive ingestion of beta-carotene in yellow, orange and green coloured vegetables and fruit. It commonly presents as a yellow or orange skin discolouration especially noticeable in the thick skin of the palms and soles.

Carrier


Carrier is one that carries or holds. In medicine it may be used for an individual who carries a disease without symptoms, typically a genetic disorder or infection.

Carriers


Carriers: plural of carrier; those that carry or hold. In medicine it may be used for individuals who carry a disease without symptoms, typically a genetic disorder or infection.

Caseating


Caseating is an adjective pertaining to cheese, a cheese-like appearance or texture.

Caseating necrosis


Caseating necrosis is a histological term for a specific form of collagen destruction typically associated with granulomas; a mix of coagulative and liquefactive necrosis resembling friable cheese.

Catagen


Catagen is the short involutional phase of the hair cycle.

Cataract


Cataract is defined in medicine as an opacity in the lens of the eye which may cause impaired vision or blindness.

Cataracts


Cataracts: plural of cataract; in medicine are opacities in the lenses of the eyes which can cause impaired vision and blindness.

Catheter


Catheter is a hollow tube used in a medical procedure to drain or infuse liquids or fluids. A urinary catheter is used to drain urine, and a venous catheter used for an intravenous infusion.

Catheters


Catheters: plural of catheter; hollow tubes used in medical procedures to drain or infuse liquids or fluids.

Cationic


Cationic is an adjective pertaining to a cation, a positively charged ion (atom or molecule).

Caudal


Caudal is an adjective pertaining to the tail. A caudal location is on or near to the tail or base of the spine.

Causative drug


Causative drug is a medication responsible for an adverse reaction, such as a rash.

Causative drugs


Causative drugs: plural of causative drug; medications responsible for an adverse reaction, such as a rash.

Cauterise


Cauterise is the verb pertaining to the process of cautery, the destruction or coagulation of tissues using heat or chemicals.

Cautery


Cautery destroys or coagulates tissue using heat or chemicals.

Cellular


Cellular is an adjective pertaining to living cells.

Cephalic


Cephalic is an adjective pertaining to the head. Cephalic location means on or near to the head.

Ceramide


Ceramide is a family of waxy lipid molecules found in cell membranes with important functions in cell regulation and apoptosis. Approximately 50% of the stratum corneum is composed of a ceramide.

Ceramides


Ceramides: plural of ceramide; members of a family of waxy lipid molecules found in cell membranes with important functions in cell regulation and apoptosis. Approximately 50% of the stratum corneum is composed of ceramides.

Cerebral


Cerebral is an adjective pertaining to the brain (cerebrum).

Cerebrovascular


Cerebrovascular is an adjective pertaining to the vascular system within the brain.

Cervical


Cervical is an adjective pertaining to the cervix, that part of the uterus (womb) that opens into the upper vagina. Cervical is also used in anatomy pertaining to the neck, so examples include the cervical spine and cervical lymph nodes.

Cervix


Cervix is that part of the uterus (womb) that opens into the upper vagina.

Cessation


Cessation is the process of ceasing or stopping, eg, the cessation of a drug means the drug is being stopped.

Chancre


Chancre(s): Noun; painless ulcer.

Chancres


Chancre(s): Noun; painless ulcer.

Checkpoint inhibitor


Checkpoint inhibitor is a drug or agent that blocks an inhibitory checkpoint molecule protecting a tumour from immune attack. It is a form of immune therapy (immunotherapy).

Checkpoint inhibitors


Checkpoint inhibitors: plural of checkpoint inhibitor; drugs that block inhibitory checkpoint molecules protecting a tumour from immune attack. Checkpoint inhibitors are a form of immune therapy (immunotherapy).

Chelating


Chelating is an adjective pertaining to chelation, the binding of metals.

Chelation


Chelation is the chemical process by which metals are bound to an organic molecule. In medicine chelation may be used to treat or remove toxic heavy metals, such as lead or mercury, from the body.

Chemokine


Chemokine is a chemotactic cytokine; a signalling molecule that induces chemotaxis in nearby cells. An inflammatory chemokine, for example, attracts leukocytes (white blood cells).

Chemokines


Chemokines: plural of chemokine; chemotactic cytokines; signalling molecules that induce chemotaxis in nearby cells. Inflammatory chemokines, for example, attract leukocytes (white blood cells).

Chemotactic


Chemotactic is an adjective pertaining to chemotaxis, the movement of organisms, cells, or cellular components, in response to a chemical stimulus.

Chemotaxis


Chemotaxis is the movement of organisms, celsl, or cellular components, in response to a chemical stimulus.

Chemotherapy


Chemotherapy is an adjective and noun pertaining to the chemical treatment of disease, eg, chemotherapy drug, chemotherapy is the drug regime to treat cancer.

Chimera


Chimera has two genetically distinct components. In biologics this means one part of the molecule is derived from a mouse and the other part is human. An individual can also be a chimera, usually of the blood system detected during blood typing.

Chimeric


Chimeric is an adjective pertaining to being a chimera, such as an individual or molecule having two genetically different parts. In the case of a biologic agent, this may mean one part of the molecule is derived from a mouse and the other part is human.

Cholestasis


Cholestasis is the buildup of bile or its constituents due to a failure to secrete or blockage.

Cholestatic


Cholestatic is an adjective pertaining to cholestasis; the build up of bile or its constituents.

Cholesterol


Cholesterol is a sterol compound present in all animal fats and oils.

Cholinergic


Cholinergic is an adjective pertaining to acetylcholine, a neurotransmitter.

Chondritis


Chondritis is inflammation of cartilage.

Chorionic villus sampling


Chorionic villus sampling is a procedure removing cells from the chorion of the placenta in the first trimester of pregnancy to identify genetic abnormalities in the fetus.

Chorionic-villus sampling


Chorionic-villus sampling is a procedure removing cells from the chorion of the placenta in the first trimester of pregnancy to identify genetic abnormalities in the fetus.

Chorioretinitis


Chorioretinitis: inflammation of the choroid layer of the retina.

Chorioretinopathy


Chorioretinopathy is a non-inflammatory condition of the eye involving both the choroid and the retina.

Chromatin


Chromatin is the DNA and protein packaged to fit into the nucleus of a cell.

Chromonychia


Chromonychia is discolouration of a nail.

Chromophore


Chromophore is the part of a molecule that imparts its colour.

Chromophores


Chromophores: plural of chromophore; the part of molecules that impart colour.

Chromosomal


Chromosomal is an adjective pertaining to the chromosome, a long chain of genes inherited as a whole.

Chromosome


Chromosome is a long chain of genes; the entity carrying the genetic material of a cell (organism) which is passed to progeny, and is expressed as proteins for cellular functions.

Chromosomes


Chromosomes: plural of chromosome; entities carrying the genetic material of a cell (organism) which are passed to progeny, and are expressed as proteins for cellular functions. Humans have 46 chromosomes in each cell nucleus.

Chronic


Chronic is an adjective pertaining to persistence. It is used in medicine to describe a persistent symptom or sign.

Chronicity


Chronicity refers to the duration of an illness.

Cicatricial


Cicatricial is an adjective pertaining to cicatrix, a scar.

Circumcision


Circumcision is the surgical removal of the penile foreskin.

Circumferential


Circumferential is an adjective pertaining to the circumference. In dermatology it may be used to describe a rash or skin change encircling or encompassing a body part such as a limb or trunk.

Circumferentially


Circumferentially is an adverb pertaining to the circumference. in dermatology it is when a skin change or rash is encircling a body part such as a limb or trunk.

Circumscribed


Circumscribed is an adjective used to describe being welldefined, having a distinct edge.

Cirrhosis


Cirrhosis is the end result of chronic inflammation and scarring of the liver. Common causes of cirrohosis include chronic alcohol abuse and viral hepatitis B and C.

Claudication


Claudication is muscle pain due to arterial insufficiency. Typically claudication occurs in the legs with exerise and indicates arteriosclerosis.

Cleavage


Cleavage is a sharp division or separation into parts.

Cleft


Cleft is a separation, split, or fissure between two parts.

Cleft lip


Cleft lip: a congenital malformation presenting as a split in the upper lip; may be unilateral or bilateral.

Cleft palate


Cleft palate: a congenital malformation presenting as an opening in the roof of the mouth.

Clefting


Clefting is the formation of a cleft, separation, split, or fissure between two parts. In medicine clefting can result from the failure of two embryonal plates to fuse as in a cleft lip or cleft palate. In histology, clefting is used when separation of cells, layers, or constituents is seen, often as a characteristic processing artefact.

Clefts


Clefts: plural of cleft; separations, splits, or fissures between parts.

Clinicopathological


Clinicopathological is an adjective pertaining to the combination of clinical and pathological. Clinicopathological correlation means the diagnosis needs be consistent with both the clinical and pathological findings.

Clod


Clod is a lump of earth. In dermoscopy it may be used to mean a globule, ovoid nest, or lacuna.

Clods


Clods: plural of clod; in dermoscopy clods may be globules, ovoid nests or lacunae.

Clonal


Clonal is an adjective pertaining to a clone; an expansion from a single entity.

Clone


Clone is an expansion from a single entity, so all members are identical.

Clones


Clones: plural of clone; more than one expansion, each from an individual single entity. Members within each of the clones are identical.

CNS


CNS is the acronym for central nervous system; the brain and spinal cord.

Coagulase


Coagulase is an enzyme that converts fibrinogen to fibrin resulting in a blood clot and blood cell clumping. Coagulase is produced by some staphylococci and the coagulase test is used to determine pathogenicity.

Coagulation


Coagulation is the process by which blood forms a clot.

Coagulopathy


Coagulopathy is a disorder of coagulation that results in thrombosis, clotting. There are many forms of coagulopathy and those with skin signs can be divided into systemic coagulopathy and vascular coagulopathy.

Coalesce


Coalesce is a verb meaning to merge together to form one. Skin papules may coalesce to form a plaque.

Coalescence


Coalescence is a noun for a merging of mutiples into a single entity, eg, a coalescence of vesicles into a bulla.

Coalescing


Coalescing is an adjective and verb pertaining to coalescence, the coming together or merging to form one. In dermatology, coalescing papules may form a plaque; papules coalescing into plaques.

Colitis


Colitis is inflammation of the colon (large intestine).

Collagen


Collagen is a large family of proteins with a triple helix structure found in most tissues. In the skin, collagen is an important and major component of the dermis.

Collagenoma


Collagenoma is a variant of connective tissue naevus; a congenital hamartoma of increased dermal collagen without an increase in fibroblast numbers. The Shagreen patch of tuberous sclerosis is usually a collagenoma on histology.

Collagenomas


Collagenomas: plural of collagenoma; variant of connective tissue naevi; congenital hamartomas of increased dermal collagen without an increase in fibroblast numbers.

Collagenous


Collagenous is an adjective used in histology pertaining to collagen, eg, a collagenous stroma.

Collarette of scale


Collarette of scale refers to a rim of fine white scale at the edge of an inflammatory lesion or resolving infectious process.

Colonoscope


Colonoscope is an endoscope, a long tubular instrument with light and magnification, for examining and sampling the large bowel (colon, large gut).

Colonoscopy


Colonoscopy is the visual examination of the colon (large gut, large bowel) using a colonoscope, a specific type of endoscope.

Colposcope


Colposcope is an instrument providing light and magnification for examining the vagina and cervix.

Colposcopy


Colposcopy is an intravaginal examination using a colposcope to provide light and magnification; most often used to identify cervical dysplasia.

Columella


Columella of the nose separates the nostrils, connecting the tip of the nose to the base of the nose. It is the visible outside edge of the nasal septum composed of skin and cartilage.

Comedo


Comedo is a blocked hair follicle (pore) in the skin. Skin cell debris combines with oil (sebum) to plug the follicle. A comedo can be open (blackhead) or closed by skin (whitehead).

Comedogenic


Comedogenic is an adjective pertaining to the formation of comedones, hair follicles blocked with sebum and skin cell debris.

Comedogenicity


Comedogenicity is a measure of the tendency to cause comedones. Cosmetics may be assessed for comedogenicity.

Comedones


Comedones: plural of comedo; pores filled with skin debris, and sebum (oil).

Commensal


Commensal is an adjective and noun pertaining to a close relationship between unrelated organisms without harm to either, and sometimes with benefit to one or both.

Commensals


Commensals: plural of commensal (the noun); typically used for the micro-organisms living on a body surface and forming the microbiome.

Community infection


Community infection is a viral, bacterial, or other type of infection that is common in the general population.

Community infections


Community infections: plural of community infection; viral, bacterial, or other infections that are common In a general population.

Complement


Complement is a system of glycoproteins important in the innate immune system. Activation of the complement cascade results in enhancement of the cellular immune response.

Complementarity


Complementarity is a noun meaning a situation in which two parts match. In biology this may refer to the base-pair matches in double-stranded DNA or RNA, an enzyme matches a substrate, or an antibody matches an antigen.

Compound naevi


Compound naevi: plural of compound naevus (American spelling nevi/naevus); benign melanocytic naevi in which the melanocytes are located in both the epidermis and dermis.

Compound naevus


Compound naevus (American spelling nevus) is a benign melanocytic naevus in which melanocytes are found in both the epidermis and dermis.

Compulsion


Compulsion is a repetitive behavioural or mental act that the individual feels compelled to perform to reduce the distress elicited by an obsession.

Compulsions


Compulsions: plural of compulsion; repetitive behavioural or mental acts that the individual feels compelled to perform to reduce the distress elicited by the obsessions.

Compulsive


Compulsive is an adjective pertaining to a compulsion, an irresistible urge.

Computed tomography


Computed tomography (acronym CT scan) is a diagnostic radiology test that scans the body to produce cross-sectional images of the part.

Computed tomography (CT)


Computed tomography (CT) is a diagnostic radiology test that scans the body to produce cross-sectional images of the part.

Concentric


Concentric is an adjective pertaining to arrangement around a central point, eg, an archery or shooting target is concentric rings around the central bull's eye.

Concomitant


Concomitant is an adjective meaning accompanying or at the same time, simultaneous, eg, concomitant treatments means more than one treatment at the same time.

Concomitantly


Concomitantly is an adverb pertaining to concomitant or simultaneous. Medications may be used concomitantly meaning used at the same time.

Concurrent


Concurrent is an adjective to describe co-existing, happening or done at the same time.

Conduction


Conduction is the process of transferring heat or electricity.

Configuration


Configuration is an arrangement or shape. In dermatology many skin conditions have a characteristic configuration (arrangement).

Confluent


Confluent is an adjective pertaining to confluence, flowing or coming together, eg, confluent pustules.

Congenital


Congenital is an adjective to mean present at birth, born with.

Conjugate


Conjugate is a noun and verb pertaining to the joining together of parts. Examples include the joining of two molecules such as a fluorofor and an antibody to use in direct immunofluoresence, to conjugate a verb in grammar, bacteria conjugate to share genetic material,

Conjugated


Conjugated is the past tense of the verb to conjugate meaning to be paired or joined.

Conjugates


Conjugates: plural of conjugate (the noun); parts paired or joined; and present tense of the verb to conjugate meaning to pair or join together.

Conjunctiva


Conjunctiva is the membrane that covers the inside of the eyelid and surface of the eyeball.

Conjunctivae


Conjunctivae: plural of conjunctiva; membranes that cover the inside of the eyelids and surfaces of the eyeballs.

Conjunctivitis


Conjunctivitis is inflammation of the conjunctiva of the eye.

Connective tissue


Connective tissue is found throughout the body, holding layers or components together. In the skin this refers to the dermis and subcutaneous tissue, connecting the epidermis to underlying layers such as muscle.

Consanguinity


Consanguinity is a close genetic relationship between parents; kinship; having a common ancestor. Consanguinity increases the risk of a child inheriting an autosomal recessive genetic disorder.

Constituent


Constituent is a component, a part.

Constituents


Constituents: plural of constituent; components or parts.

Constriction


Constriction is used to mean a narrowing of something, such as a blood vessel.

Contracture


Contracture is a permanent shortening of muscle, connective tissue, or skin typically resulting in deformity across a joint.

Contractures


Contractures: plural of contracture; deformities caused by permanent shortening of tissues across joints.

Contraindicated


Contraindicated is a verb related to inadvisable, not indicated. In medicine it is used in relation to the inadvisability of a treatment, procedure or investigation, and may be categorised as relatively or absolutely contraindicated.

Contraindication


Contraindication is a reason why a treatment, procedure or investigation is inadvisable. A contraindication may be relative (care needed to proceed, eg, use a lower dose) or absolute (must not proceed). Pregnancy is an absolute contraindication for some drugs and procedures such as x-rays.

Contraindications


Contraindications: plural of contraindication; reasons why a treatment, procedure or investigation is inadvisable. Contraindications may be relative or absolute.

Control


Control can be used as a noun, verb, or adjective, usually pertaining to the power to direct or restrain. In a scientific experiment or clinical trial, a control (noun) is a comparison without an active intervention. Control can be used as a verb for the suppression of a symptom or condition, for example to control itch means to be not itchy anymore.

Controls


Controls can be used as the plural of the noun, or as a present tense of the verb to control (to direct or restrain). In scientific experiments and clinical trials the controls are those used as comparisons with no active interventions.

Convulsant


Convulsant is a trigger for a convulsion, for example, a toxin or drug that causes involuntary muscle contractions. An anti-convulsant prevents convulsions.

Convulsion


Convulsion is the process of having an episode of uncontrollable muscle contractions as can occur with epilepsy.

Convulsions


Convulsions: plural of convulsion; episodes of uncontrollable muscle contractions.

Cord


Cord is a rounded long flexible structure like a rope. Examples in anatomy include the spinal cord, umbilical cord, and spermatic cord. In dermatology palpable linear firm structures deep in the skin may be described as cords as in Dupuytren contracture and Interstitial granulomatous dermatitis.

Cords


Cords: plural of cord; rounded long flexible structures like ropes.

Cornea


Cornea is the transparent layer at the front of the eye.

Corneocyte


Corneocyte is an epidermal cell (keratinocyte) in the stratum corneum (outermost layer of the epidermis) which normally lacks a nucleus.

Corneocytes


Corneocytes: plural of corneocyte; epidermal cells (keratinocytes) in the stratum corneum which normally lack nuclei.

Corneotherapy


Corneotherapy is a medically funded treatment with dermatological cosmetics administered by medical staff.

Cornoid


Cornoid is an adjective meaning horn-like, eg, cornoid lamella is a thin horn-like layer.

Corticosteroid


Corticosteroid is a family of steroid hormones made in the adrenal gland cortex comprising glucocorticosteroids (glucocorticoids) and mineralocorticosteroids (mineralocorticoids).

Corticosteroids


Corticosteroids: plural of corticosteroid; includes glucocorticosteroids and mineralocorticosteroids; steroid hormones made in the adrenal gland cortex or synthetically for use as a topical, inhaled, or systemic medication.

Cortisol


Cortisol, also known as hydrocortisone, is a glucocorticosteroid hormone made in the cortex of the adrenal gland.

Cosmeceutical


Cosmeceutical is a substance or product that claims both cosmetic and therapeutic benefits.

Cosmeceuticals


Cosmeceuticals: plural of cosmeceutical; substances or products that claim both cosmetic and therapeutic benefits.

Cream


Cream, when used in dermatology, is a semi-solid formulation for topical application. A cream may be a water in oil (lipid) emulsion or lipid (oil) in water emulsion. Common usage also makes cream a verb, to apply a cream.

Creams


Creams; plural of cream; in dermatology creams are semi-solid formulations for topical application.

Crepitus


Crepitus is a crackling sound. It can be heard when there is gas in tissues such as gas gangrene; in pneumonia; and when bones rub together after a fracture.

Cribriform


Cribriform is an adjective used to describe something pierced by many little holes.

Cross-reactivity


Cross-reactivity, when used in allergology, is when reactions occur to two or more different agents because they appear similar to the immune system.

CRP


CRP is the acronym for C-reactive protein; a nonspecific inflammatory marker protein produced by the liver and commonly measured in the blood. An elevated CRP in the blood is associated with infection, tumours, and inflammatory diseases.

Crust


Crust, when used in medicine, is dried body exudate. On the skin surface, a crust may be formed from dried serum, blood, or pus. Crust is also used in dermatopathology for a dry concretion of parakeratotic keratinocytes, serum, and inflammatory cells within the stratum corneum.

Crusted


Crusted is an adjective or verb pertaining to a crust or its formation. In dermatology, a rash may be described as having a crusted appearance or becomes crusted.

Crusting


Crusting is a verb which, when used in dermatology, is the formation of dried serum, blood or pus on the surface of the skin.

Cryoglobulin


Cryoglobulin is an immunoglobulin that precipitates out in the blood on exposure to cold.

Cryoglobulins


Cryoglobulins: plural of cryoglobulin; immunoglobulins that precipitate out in the blood on exposure to cold.

Cryotherapy


Cryotherapy is treatment using a very cold substance such as liquid nitrogen or dry ice. In dermatology, cryotherapy is often used to treat warts or actinic keratoses.

Crypt


Crypt is a chamber or room under the surface. So in dermatology, a crypt is a tube or recess extending down from the skin surface.

Cryptorchidism


Cryptorchidism is undescended testes (testicles).

Crypts


Crypts: plural of crypt; in dermatology, recesses or tubes extending down from the skin surface.

CT


CT is the acronym for computed tomography; a CT scan is a diagnostic radiology test that produces cross-sectional images of the body.

Cubital


Cubital is an adjective pertaining to the ulna bone in the forearm. The cubital (also called antecubital) fossa is the elbow crease anterior to (in front of) the elbow.

Culture


Culture is a noun and verb with many meanings, including: sociological, ie, the cultural practices or characteristics of a particular race or population; manners or taste, ie, to be cultured or refined; the artificial propagation of organisms, eg, a bacterial culture; a verb such as to culture a wound swab for bacteria.

Cumulative


Cumulative is an adjective pertaining to accumulation; describes increasing by successive additions.

Cutaneous


Cutaneous is an adjective pertaining to the skin.

Cuticle


Cuticle is the outermost layer of a hair, and is also the transparent layer of dead cells that connects the proximal nailfold to the nail plate.

Cutis


Cutis is the Latin word for skin.

Cyanosis


Cyanosis is the bluish colouration of the skin and mucous membranes due to deoxyhaemoglobin in the surface capillaries. This may be seen in either heart or lung disorders causing inadequate oxygenation, or when cold and the peripheral circulation is sluggish.

Cyclic


Cyclic: occurring in cycles, recurring regularly.

Cyclical


Cyclical: an adjective pertaining to a cycle; recurring.

Cynomolgus monkeys


Cynomolgus monkeys is the laboratory name for long-tailed or crab-eating macaques, Macaca fascicularis.

Cyrano nose


Cyrano nose has an enlarged tip, usually due to an infantile haemangioma. It is named for Cyrano de Bergerec, an historical figure said to have had a large nose.

Cyst


Cyst is a thin-walled closed capsule or sac-like structure, filled with fluid, solid or semisolid material. Cysts have an epithelial lining.

Cystic


Cystic is an adjective pertaining to a cyst, an enclosed space in a tissue containing fluid, solid or semi-solid material.

Cysts


Cysts: plural of cyst; thin-walled capsules containing fluid or semifluid material with an epithelial lining.

Cytogenetic


Cytogenetic is an adjective pertaining to cytogenetics, the study of chromosomes and their structure.

Cytogenetics


Cytogenetics is the study of chromosomes and their structure. It is a branch of cytology that specifically looks at the number and structure of chromosomes.

Cytokeratin


Cytokeratin is better known as keratin, a family of cytoplasmic proteins in epithelial cells.

Cytokeratins


Cytokeratins: plural of cytokeratin; better known as keratins, a family of cytoplasmic proteins in epithelial cells.

Cytokine


Cytokine is a low molecular-weight molecule that acts as an intercellular messenger. Interleukins, interferons, colony-stimulating factors, and chemokines are examples of specific types of cytokine.

Cytokines


Cytokines: plural of cytokine; low molecular-weight intercellular messengers.

Cytology


Cytology is the study of the structure and function of cells.

Cytopenic


Cytopenic: adjective pertaining to cytopenia, a reduction blood cell numbers.

Cytoplasm


Cytoplasm is the fluid inside a living cell.

Cytoplasmic


Cytoplasmic is an adjective pertaining to the cytoplasm of a cell, the fluid part of a living cell.

Cytotoxic


Cytotoxic is an adjective pertaining to cell-killing via toxins. Examples include cytotoxic drugs or cytotoxic lymphocytes.

D


Darier sign


Darier sign is positive when stroking the skin or lesion induces wealing; typically seen in cutaneous mastocystosis.

De novo


De novo is an adjective pertaining to new; in medicine it describes a condition that has occurred without a precursor.

De-novo


De-novo is an adjective pertaining to new; in medicine it describes a condition that has occurred without a precursor.

Debride


Debride is a verb meaning to remove infected or dead tissue to aid healing.

Debridement


Debridement is the process of removing infected or dead tissue to aid the healing process.

Debriding


Debriding is a form of the verb to debride, meaning to remove infected or dead tissue to aid the healing process.

Decompression


Decompression is the process of reducing the pressure of a gas.

Deform


Deform is a verb meaning to change the form, shape, or structure.

Deformities


Deformities: plural of deformity; malformations.

Deformity


Deformity is a malformation.

Degenerative


Degenerative is an adjective pertaining to loss of function or quality, eg, a degenerative disease.

Degranulation


Degranulation is the process by which cells release granules and their contents.

Demarcated


Demarcated is an adjective and verb to demarcate pertaining to separation or distinguishable. In dermatology it can refer to the boundary or division between two areas.

Demarcation


Demarcation is a noun meaning the boundary or plane of separation between two areas.

Dendrite


Dendrite is a long finger-like process of a cell that usually connects to another cell allowing direct intercellular passage of information or material.

Dendrites


Dendrites: plural of dendrite; long finger-like processes of cells that usually connect to other cells allowing direct intercellular passage of information or material.

Dendritic cell


Dendritic cell has long finger-like processes called dendrites. Examples of a dendritic cell include a neurone, melanocyte, Langerhans cell, and some types of tissue macrophage (immune cell).

Dendritic cells


Dendritic cells: plural of dendritic cell; cells with long finger-like processes (dendrites), and include neurones, melanocytes, Langerhans cells and some tissue macrophages (immune cells).

Deoxyribonucleic acid


Deoxyribonucleic acid (DNA) is a long double-helical molecule that can encode genes.

Dependent


Dependent is an adjective meaning to be subordinant or below in a relationship. In medicine it is used to describe a body part that is below the rest of the body, eg, normally the feet are dependent compared to the trunk.

Depigmentation


Depigmentation is the loss of skin pigment.

Deposition


Deposition is the process of depositing or the laying down of something. In the skin an example would be amyloid undergoing deposition. Deposition can also be used as a noun for the thing that is being deposited, eg, a deposition of amyloid.

Depositions


Depositions: plural of deposition; the things being laid down. An example is haemosiderin depositions in venous eczema.

Dermal


Dermal is an adjective pertaining to the skin, or more specifically to the dermis.

Dermal naevus


Dermal naevus (American spelling nevus) is a benign melanocytic naevus in which the melanocytes are entirely within the dermis. Dermal naevus is also called an intradermal naevus.

Dermatitis


Dermatitis is inflammation of the skin, but is mostly used more specifically as a synonym for eczema, ie, spongiotic inflammation of the epidermis.

Dermatologist


Dermatologist is a medical or surgical specialist in diseases of skin, hair, and nails. Refer to, What is a Dermatologist.

Dermatologists


Dermatologists: plural of dermatologist; medical or surgical specialists in diseases of the skin, hair, and nails.

Dermatology


Dermatology is the study of skin, hair and nails.

Dermatomal


Dermatomal is an adjective pertaining to a dermatome, an area of skin innervated by a single sensory spinal nerve, eg, shingles follows a dermatomal pattern.

Dermatome


Dermatome is the area of skin innervated by a single sensory spinal nerve. A dermatome is also a tool for taking fine slices of skin.

Dermatopathologist


Dermatopathologist is a medical specialist in the pathology of skin diseases.

Dermatopathologists


Dermatopathologists: plural of dermatopathologist; medical specialists in the pathology of skin diseases.

Dermatopathology


Dermatopathology is the study of the microscopic appearance of skin diseases.

Dermatoscope


Dermatoscope, also known as a dermoscope, is a handheld tool for examining the skin, nails, and hair, comprising a power source, light and magnification.

Dermatoscopic


Dermatoscopic is an adjective pertaining to the use of a dermatoscope (dermoscope); a handheld tool for examination of the skin, nails, and hair under magnification.

Dermatoscopy


Dermatoscopy, also called dermoscopy, is the use of a dermatoscope (dermoscope) to examine the skin, hair and nails.

Dermatoscopy or dermoscopy


Dermatoscopy refers to the use of a special magnifying device (a dermatoscope) to examine the skin, hair and nails.

Dermatoses


Dermatoses: plural of dermatosis; diseases of the skin.

Dermatosis


Dermatosis is a general term for any disease of the skin.

Dermis


Dermis is the fibrous layer of the skin immediately below the epidermis. This layer is composed predominantly of collagen but also elastin fibres which contribute to the pliability of the skin. The dermis also contains blood vessels, nerves, and adnexal structures including hair follicles, sweat, scent and sebaceous glands.

Dermopathies


Dermopathies: plural of dermopathy; diseases of the skin.

Dermopathy


Dermopathy is any disease of the skin. However it is also used in the names of specific skin diseases such as restrictive dermopathy.

Dermoscope


Dermoscope, also known as a dermatoscope, is a handheld tool for examining the skin, nails and hair, comprising a power source, light and magnification.

Dermoscopic


Dermoscopic is an adjective pertaining to the use of a dermoscope (dermatoscope); a handheld tool for examining the skin, nails, and hair under magnification.

Dermoscopy


Dermoscopy, also known as dermatoscopy, is the use of a dermoscope (dermatoscope) to examine the skin, nails, and hair under magnification.

Desensitisation


Desensitisation (American spelling desensitization) is a process of reversing a hypersensitivity reaction such as an allergy.

Desmoglein


Desmoglein is one of a family of molecules involved in forming desmosomes, the intercellular junctions that stick skin cells (keratinocytes) together. There are three main types of desmoglein in the skin.

Desmogleins


Desmogleins: plural of desmoglein; desmogleins are a family of molecules involved in forming desmosomes, the intercellular junctions that stick skin cells (keratinocytes) together. There are three main desmogleins in the skin.

Desmoplasia


Desmoplasia is a fibrous connective tissue reaction typically related to specific tumours.

Desmoplastic


Desmoplastic is an adjective used in histology pertaining to desmoplasia, the presence of a fibrous connective tissue reaction typically related to specific tumours.

Desmosome


Desmosome is a structure that holds adjacent epidermal skin cells (keratinocytes) tightly together, rather like cement between bricks.

Desmosomes


Desmosomes: plural of desmosome; the structures that hold adjacent epidermal skin cells (keratinocytes) tightly together, rather like cement between bricks.

Desquamation


Desquamation is the peeling of skin, coming off in scales, loss of squames.

Develop


Develop is a verb meaning to change, grow or progress over time.

Developing


Developing is an adjective and verb pertaining to development, the process of growth, change and evolution with time.

Development


Development is the process of growth or progress over time.

Developmental


Developmental is an adjective pertaining to development, the process of growth or progress over time.

Dexterity


Dexterity is the skill of using the hands.

Dialysis


Dialysis is a process using a membrane to separate particles in a liquid based on size. In medicine this process can be used to remove waste products and fluid from the body, eg, dialysis for renal failure can be by haemodialysis or peritoneal dialysis.

Diascopy


Diascopy is a test using pressure from clear glass or plastic to see if a rash or lesion blanches. Diascopy also allows assessment of the underlying colour.

Differential diagnosis


Differential diagnosis is a list of conditions with similar symptoms or signs needed to be considered as possibie diagnoses.

Differentiated


Differentiated is a past tense of the verb to differentiate, to make a distinction. It can also be used as an adjective, for example, well-differentiated tumour cells closely resemble normal cells from that tissue, compared to poorly differentiated meaning no longer resembles its parent cell/tissue.

Differentiation


Differentiation is the process of making different. In the skin the differentiation of a cell is the process of maturation and specialisation.

Diffuse


Diffuse is an adjective and verb pertaining to spread over a wide area. In dermatology, diffuse is used as an adjective to describe a change that is not localised or patchy, eg, diffuse alopecia compared to patchy alopecia.

Digit


Digit is a finger or toe.

Digits


Digits: plural of digit; fingers and toes.

Diploid


Diploid is an adjective describing a cell having two sets of chromosomes, as is typically seen in a normal somatic cell.

Discharge


Discharge is a verb and noun pertaining to emergence, exit or flow out, eg, to discharge a patient from hospital; and a secretion or excretion emerging from the body., such as a vaginal discharge.

Discoid


Discoid is an adjective to describe being round like a disk. In dermatology it is used to describe lesions that are circular or oval and often well-defined, eg, discoid eczema and discoid lupus.

Discrete


Discrete is an adjective to describe being separate or distinct. For example, a discrete lesion is separated from other lesions by normal skin.

Disseminate


Disseminate is a verb to scatter or distribute widely.

Disseminated


Disseminated is an adjective to describe being scattered or widespread and derives from the verb to disseminate meaning to scatter. Disseminated is therefore also the past tense of the verb. Examples in dermatology may include an infection that gained entry through the skin disseminated throughout the body; a rash may present as disseminated lesions distributed/scattered widely over most of the body surface.

Distal


Distal is an adjective to describe being furthest from the point of origin or closest to the end. Anatomically this may mean being furthest from the centre of the body.

Distribution


Distribution is the localisation or pattern. The distribution of a dermatosis refers to the pattern or localisation of skin lesions, and can be quite characteristic for a specific condition.

DLQI


DLQI is the acronym for Dermatology Life Quality Index, a tool used for assement of the impact of a skin disease on the patient.

DNA


DNA is the acronym for deoxyribonucleic acid, a long nucleic acid chain that can encode genes, the famous double helix.

Dolichocilia


Dolichocilia is unusually long eyelashes.

Dorsal


Dorsal is an adjective pertaining to the back or posterior part. A dorsal location means on the upper surface or back of a body part.

Dorsum


Dorsum is a noun used in anatomy to mean the back, eg, the back of the trunk or the back of a hand.

Double-blind


Double-blind is an adjective used to describe clinical trials in which neither the participants nor the researchers know which treatment or intervention has been selected for the individual, ie, both the assessor and the participant are blinded to the intervention.

Duplex ultrasonography


Duplex ultrasonography combines two types of ultrasound to produce a scan of blood flow in arteries and veins.Traditional ultrasonography scans a fixed object (ie, the artery or vein) and is combined with a Doppler scan of moving objects (ie, blood flow). Uses of duplex ultrasonography include identification of a DVT, incompetent valves in varicose veins, or to map out vessels for sclerotherapy.

Duplex ultrasound


Duplex ultrasound is an imaging test combining two types of ultrasound to produce a scan of blood flow in arteries and veins. Traditional ultrasound scans a fixed object (ie, the artery or vein), and is combined with a Doppler scan of moving objects (ie, blood flow). Uses for duplex ultrasonography scan include identification of a DVT, incompetent valves in varicose veins, or to map out vessels for sclerotherapy.

Duplex-ultrasound scan


Duplex-ultrasound scan combines two types of ultrasound to produce a scan of blood flow in arteries and veins. Traditional ultrasound scans a fixed object (ie, the artery or vein), and is combined with a Doppler scan of moving objects (ie, blood flow). Uses for duplex ultrasonography scan include identification of a DVT, incompetent valves in varicose veins, or to map out vessels for sclerotherapy.

Dysaesthesia


Dysaesthesia (American spelling dysesthesia) literally means abnormal (dys) sensation (aesthesia) and describes unpleasant, uncomfortable sensations produced by ordinary stimuli. There are many specific types of dysaesthesia, eg, orodynia, pruritus ani, brachioradial pruritus, male genital dysaesthesia, etc.

Dysbacteriosis


Dysbacteriosis, also called dysbiosis, is an imbalance in the microbial community (microbiome) of a specific body site, eg, the skin, vagina, bowel.

Dysbiosis


Dysbiosis, also called dysbacteriosis, is an imbalance in the microbial community (microbiome) of a specific body site, eg, the skin, vagina, bowel.

Dysfunction


Dysfunction is malfunction, an abnormal function.

Dysfunctional


Dysfunctional is an adjective pertaining to dysfunction, an abnormal or malfunctioning state or situation.

Dysgeusia


Dysgeusia is abnormal or disturbed sense of taste.

Dyskeratosis


Dyskeratosis is a histological term for premature or altered (abnormal) keratinocyte differentiation.

Dyskeratotic


Dyskeratotic is an adjective used in histology pertaining to dyskeratosis; premature or abnormal keratinisation of cells in the epidermis.

Dyslipidaemia


Dyslipidaemia (American spelling dyslipidemia) is an abnormally high level of one or more lipids or lipoproteins in the bloodstream.

Dysmorphia


Dysmorphia is a deformity or abnormality in shape or size of a body part.

Dysmorphic


Dysmorphic is an adjective pertaining to an anatomical malformation.

Dyspareunia


Dyspareunia is the medical term for painful sexual intercourse.

Dysphagia


Dysphagia is difficulty in swallowing.

Dyspigmentation


Dyspigmentation is any abnormality in the distribution of pigment in the skin.

Dysplasia


Dysplasia is the abnormal growth or development of cells or organs.

Dysplastic


Dysplastic is an adjective pertaining to dysplasia, abnormal or atypical appearance of a cell or tissue.

Dysregulate


Dysregulate is a verb meaning to inhibit or prevent a controlling mechanism. It is used in medicine to mean the inhibition or prevention of a physiological control.

Dysregulated


Dysregulated is the past tense of the verb to dysregulate, meaning to inhibit or prevent a controlling mechanism. In medicine it is used when there has been an abnormality or impairment of a physiological control. A process has been dysregulated.

Dysregulation


Dysregulation is the failure to control or regulate a physiological mechanism or process.

Dysrhythmia


Dysrhythmia: an irregular heart beat.

Dysrhythmias


Dysrhythmias: plural of dysrhythmia, an irregular heart beat.

Dystonia


Dystonia refers to uncontrollable muscle contractions and movements. Dystonia be localised to one muscle group or generalised to the entire body.

Dystrophic


Dystrophic is an adjective pertaining to dystrophy, a weakening or degeneration of a tissue.

Dystrophy


Dystrophy refers to degeneration or abnormal formation of tissue due to disease or malnutrition. A well-known example is muscular dytrophy caused by a genetic mutation. An example in dermatology is nail dystrophy, meaning a nail that did not develop normally or has become abnormal due to a disease such as tinea.

Dysuria


Dysuria is a burning painful sensation when passing urine.

E


EASI


EASI is the acronym for Eczema Area and Severity Index, a tool used for assessment and monitoring of atopic eczema.

Ecchymoses


Ecchymoses: plural of ecchymosis; bruises; large purpura; discolourations due to bleeding under the skin.

Ecchymosis


Ecchymosis is a bruise; a discolouration due to bleeding under the skin.

Eccrine


Eccrine is an adjective derived from the Greek to secrete.

Eccrine gland


Eccrine gland is the common sweat gland in the skin.

Eccrine glands


Eccrine glands: plural of eccrine gland; the common sweat glands found deep in the dermis.

ECG


ECG (American terminology EKG) is the acronym for electrocardiogram; graph of the electrical activity of the heart.

Echocardiogram


Echocardiogram ('echo' for short) uses ultrasound waves to produce a live video of the heart to assess size, muscle and valve function. The most common type of echocardiogram is done through the chest wall (transthoracic) using a transducer applied to the skin of the chest. A stress echocardiogram assesses heart function before and again after excercise when the heart is pumping harder. The third type is called a transoesophageal echocardiogram.

Echocardiograms


Echocardiograms: plural of echocardiogram; use ultrasound waves to produce live videos of the heart to assess size, muscle and valve function. Echocardiograms come in three types: transthoracic, transoesophageal, and stress test.

Eclabion


Eclabion: plural of eclabium; turning out of the lips.

Eclabium


Eclabium is a turned-out lip; eversion of a lip.

Ectasia


Ectasia is a widening or dilation of a tube-like structure such as a blood vessel.

Ectodermal


Ectodermal is an adjective pertaining to the ectoderm. An example is ectodermal dysplasia. The ectoderm is the outermost of the three primary germ layers of an embryo (the other two being mesoderm and endoderm). Ectoderm develops into epidermis and neural tissue.

Ectopic


Ectopic is an adjective pertaining to not being in the right place, eg, an ectopic pregnancy has developed somewhere other than inside the uterus.

Ectropion


Ectropion is a turned out part. Common usage has ectropion meaning the eversion (turning out) of a lower eyelid resulting in exposure of the inside surface of the eyelid.

Eczema


Eczema, also called dermatitis, is an inflammatory condition of the skin defined histologically by the presence of epidermal spongiosis.

Eczematous


Eczematous is an adjective pertaining to eczema, resembling eczema, being eczema-like.

Efficacy


Efficacy is a noun for achieving a desired effect, eg, the efficacy of a treatment.

Effluvium


Effluvium, when used in dermatology, refers to diffuse hair loss of various causes. In general usage, an effluvium is an unpleasant gaseous smell.

Elastic fibre


Elastic fibre (American spelling fiber) is composed of elastin and microfibrils of fibrillin, collagen VI, and other proteins and glycoproteins. An elastic fibre demonstrates elasticity, the ability to stretch and return to the original.

Elastic fibres


Elastic fibres: plural of elastic fibre (American spelling fibers/fiber); are composed of elastin and microfibrils of fibrillin, collagen VI and other proteins and glycoproteins. Elastic fibres form a meshwork to provide elasticity in the dermis, arterial walls, and the back of the eye.

Elastin


Elastin is one of the proteins making up elastic fibres. Elastin is probably produced by fibroblasts.

Elastolysis


Elastolysis is a histological term used to describe the loss or destruction of connective tissue elastic fibres.

Elastolytic


Elastolytic is an adjective pertaining to elastolysis, the breakdown and loss of elastic fibres.

Elastoma


Elastoma is a variant of connective tissue naevus; a congenital hamartoma characterised by increased elastic fibres.

Elastomas


Elastomas: plural of elastoma; congenital hamartomas composed of increased elastic fibres.

Elastosis


Elastosis is a histological term for an increase in the elastic fibres in the skin.

Elastotic


Elastotic is an adjective used in histology pertaining to elastic tissue and fibres. Due to observed histological changes, elastotic often finds its way into the name of the condition as well.

Electrocardiogram


Electrocardiogram (ECG, American terminology EKG)) is a graph of the electrical activity of the heart.

Electrocardiography


Electrocardiography is the process of performing an electrocardiogram, a graph of the electrical activity of the heart.

Electron microscopy


Electron microscopy is a laboratory tool used to examine extremely thin specimens with a beam of electrons passed through an electromagnetic lens. Electron microscopy allows visualisation of much smaller structures than light microscopy.

Electrophoresis


Electrophoresis is a laboratory technique to separate molecules by their electric charge and size using an electric field.

Emboli


Emboli: plural of embolus; small particles carried through the bloodstream to block small blood vessels. Examples include air bubbles, blood clots, and clumps of bacteria.

Embolic


Embolic is an adjective pertaining to an embolus (emboli), small piece(s) of foreign material in a blood vessel causing a blockage.

Embolisation


Embolisation is the process of forming an embolus, typically blocking a blood vessel. Embolisation can be a pathological process such as occurs in a pulmonary embolus, or may be a medical procedure to block or close off abnormal vessels.

Embolism


Embolism is the obstruction of a blood vessel(s) by an embolus/emboli, small piece(s) of a foreign material.

Embolisms


Embolisms: plural of embolism; blockages of blood vessels by small pieces of foreign material.

Embolus


Embolus is a small particle that has been carried through the bloodstream and blocks a small blood vessel. The particle is foreign to the bloodstream and examples include an air bubble, fat, clump of bacteria, or blood clot.

Emollient


Emollient derives from the Latin to soften, so an emollent is a moisturiser that softens the skin.

Emollients


Emollients: plural of emollient; moisturisers that soften the skin.

Enanthem


Enanthem, also called an enanthema, is a rash on mucous membranes.

Enanthema


Enanthema, also called an enanthem, is a rash occurring on mucous membranes.

Enanthemata


Enanthemata: plural of enanthem; rashes on mucous membranes.

Enanthems


Enanthems, plural of enanthem(a), rashes on the mucous membranes, usually due to a viral infection.

Encapsulated


Encapsulated is an adjective and verb pertaining to being within a capsule. A medication may be encapsulated, ie, in a capsule form rather than a tablet. In histology encapsulated describes a pathological process being contained by a membrane or wall, eg, a cyst is encapsulated by the fibrous wall. Microorganisms can also be encapsulated by a protective thick mucoid or polysaccharide layer.

Encephalitis


Encephalitis is inflammation of the brain.

Encephalopathy


Encephalopathy is a general term covering a range of temporary or permanent disorders of brain function, including those caused by toxins or infections.

Encysted


Encysted: past tense of the verb to encyst; pertains to enclosed walled-off stage of primitive organisms such as protozoa; often inactive.

Endemic


Endemic is an adjective used to describe being constantly present in a population or region, eg, an endemic disease may be due to an infectious organism or arthropod that spreads an infection occurring in an area due to climatic factors.

Endocarditis


Endocarditis is inflammation of the heart valves and lining of the heart muscle.

Endocrine


Endocrine is an adjective pertaining to the production and release of secretions (hormones) directly into the blood.

Endocrinological


Endocrinological is an adjective pertaining to hormones or the hormone (endocrine) system.

Endocrinologist


Endocrinologist is a medical specialist in diseases of the endocrine (hormone) system.

Endocrinologists


Endocrinologists: plural of endocrinologist; medical specialists in diseases of the endocrine (hormone) system.

Endocrinopathies


Endocrinopathies: plural of endocrinopathy; diseases of the endocrine system; hormonal problems.

Endocrinopathy


Endocrinopathy is a disease of the endocrine system; a hormonal problem.

Endogenous


Endogenous is an adjective to describe an origin from within. In medicine an endogenous cause for an illness means it has not been caused by an external agent or event, eg, atopic dermatitis is an example of an endogenous form of eczema.

Endoscope


Endoscope is an instrument introduced into a body cavity or organ to allow visual examination.

Endoscopic


Endoscopic is an adjective pertaining to the use of an endoscope, an instrument introduced into a body cavity or organ to allow direct visual examination.

Endoscopy


Endoscopy is the use of an endoscope, an instrument introduced into a body cavity or organ allowing direct visual examination.

Endothelial


Endothelial is an adjective pertaining to cells derived from the embryonal mesoderm to form the endothelium lining blood vessels and heart cavities, eg, endothelial cells.

Endothelium


Endothelium is the layer of cells that line the blood vessels and the heart.

Endovenous


Endovenous is an adjective to describe being inside a vein.

Entheses


Entheses: plural of enthesis; connections between ligaments or tendons and bones.

Enthesis


Enthesis is the connection between a tendon or ligament and bone.

Enthesitis


Enthesitis is inflammation of an enthesis, the connection between a tendon or ligament and bone.

Enthesopathy


Enthesopathy is any condition affecting an enthesis, where a tendon or ligament attaches to bone.

Enzymatic


Enzymatic is an adjective pertaining to enzymes; biological catalysts.

Enzyme


Enzyme is a biological catalyst involved in biochemical reactions.

Enzymes


Enzymes: plural of enzyme; biological catalysts involved in biochemical reactions.

Eosinophil


Eosinophil is a type of granulocytic white blood cell (granular leukocyte) involved in the innate immune system primarily as defence against parasitic infections. Eosinophils are pro-inflammatory and are found in large numbers in allergic inflammation.

Eosinophilia


Eosinophilia is an increase in the number of eosinophils in the peripheral blood.

Eosinophilic


Eosinophilic is an adjective pertaining to staining red with the dye eosin on microscopy. Examples include the eosinophilic cytoplasmic granules seen in eosinophils, the eosinophilic stratum corneum of the epidermis, and normal eosinophilic collagen fibres in the dermis.

Eosinophils


Eosinophils: plural of eosinophil; granulocytic leukocytes with cytoplasmic granules which stain red with eosin.

Ephilides


Ephilides: plural of ephelis; freckles.

Ephilis


Ephilis is a freckle.

Epicanthic fold


Epicanthic fold is the skin fold of the upper eyelid that covers the inner corner of the eye.

Epicanthic folds


Epicanthic folds: plural of epicanthic fold; the skin folds of the upper eyelids that cover the inner corners of the eyes.

Epidemic


Epidemic is the sudden occurrence of a disease (or other event) in excess of that normally expected. Epidemic can be used as a noun or adjective, eg, a 'flu epidemic or epidemic typhus.

Epidemics


Epidemics: plural of epidemic; sudden occurrence of diseases or other events in excess of that normally expected, eg, 'flu epidemics.

Epidemiological


Epidemiological is an adjective pertaining to epidemiology, the study of population health.

Epidemiology


Epidemiology is the study of the distribution of a disease and factors involved in the spread of that disease in populations.

Epidermal


Epidermal is an adjective pertaining to the epidermis, the outermost layer of the skin, eg, epidermal naevus.

Epidermis


Epidermis is the outer epithelial layer of the skin overlying in the dermis. It is mainly composed of keratinocytes, but also includes melanocytes, Merkel cells and other cell types in small numbers.

Epidermolytic


Epidermolytic is an adjective used in histology to describe loosening of the epidermis.

Epidermotropism


Epidermotropism is movement into or towards the epidermis. It is a histological term for the migration of cells into the epidermis typically seen in mycosis fungoides and Paget disease.

Epididymis


Epididymis is the long coiled tube connecting the testis to the urethra, which stores and transports sperm in the male. It is located in the scrotum on the back of each testis.

Epigenetic


Epigenetic is an adjective pertaining to gene expression unrelated to the genetic code itself but affected by modification such as DNA methylation.

Epigenetics


Epigenetics is the study of phenotypic change due to changes in gene expression without changes in the gene itself. An example is modification of DNA methylation.

Epinephrine


Epinephrine (British terminology adrenaline) is a hormone made in the adrenal gland, a neurotransmitter, and a drug.

Epiphyseal


Epiphyseal is an adjective relating to the epiphysis, the part of a long bone where growth occurs, eg, epiphyseal plate, epiphyseal closure.

Epistaxis


Epistaxis is bleeding from the nose.

Epithelial


Epithelial is an adjective pertaining to epithelium, the tissues forming the outer layer of the body, such as skin and linings of the respiratory, gastrointestinal, and genitourinary tracts, eg, epithelial hyperplasia.

Epithelioid


Epithelioid is an adjective used in histology to describe a resemblance to epithelium.

Epithelioid cell


Epithelioid cell is large and round with abundant eosinophilic cytoplasm, prominent vesicular nucleus, and large nucleolus.

Epithelioid cells


Epithelioid cells: plural of epithelioid cell; large round cells with abundant eosinophilic cytoplasm, prominent vesicular nuclei, and large nucleoli.

Epithelioma


Epithelioma is a benign or malignant tumour arising from epithelial cells.

Epitheliomas


Epitheliomas: plural of epithelioma; malignant or benign tumours arising from epithelium.

Epithelium


Epithelium is the thin layer that lines the body surface both externally (ie, skin), and internally (ie, mucous membranes).

Eponychium


Eponychium is the nail cuticle, the skin attaching the proximal nail-fold to the nail-plate.

Erosion


Erosion is the superficial or partial destruction of a surface such as skin, that does not scar on healing.

Erosions


Erosions: plural of erosion; multiple areas of superficial or partial destruction of a surface such as the skin.

Erosive


Erosive is an adjective pertaining to erosion, the superficial or partial destruction of a surface such as the skin.

Eruption


Eruption is a sudden appearance, explosion, outbreak. Multiple lesions on the skin that have appeared suddenly is a skin eruption.

Eruptions


Eruptions: plural of eruption; multiple lesions on the skin that appeared suddenly. It can be used either to mean multiple episodes or multiple forms of a particular eruption type.

Erythema


Erythema means red, and in dermatology it describes skin reddened by increased blood supply.

Erythematous


Erythematous is an adjective describing a red colour, eg, skin is erythematous due to increased flow of blood.

Erythrocyte


Erythrocyte is a red blood cell. These cells carry oxygen through the bloodstream to the tissues in the body.

Erythrocyte sedimentation rate


Erythrocyte sedimentation rate (acronym ESR) is a test of blood viscosity. The ESR is a nonspecific test often raised in inflammatory diseases and infections.

Erythrocytes


Erythrocytes: plural of erythrocyte; red blood cells. Erythrocytes carry oxygen through the bloodstream to the tissues in the body.

Erythrocytosis


Erythrocytosis is an abnormal increase in circulating red blood cell mass.

Erythroderma


Erythroderma is defined as redness affecting at least 90% of the skin surface.

Eschar


Eschar is a full thickness scab that develops in a healing wound. Examples include wounds caused by a thermal burn, cauterisation, or chemical burn. An eschar can be typical of some infections particularly rickettsia.

Eschars


Eschars: plural of eschar; full thickness scabs that develop in a healing wound, for example after a thermal burn or a cauterisation.

ESR


ESR is the acronym for erythrocyte sedimentation rate, a test of blood viscosity. The ESR is a nonspecific test often raised in inflammatory diseases and infections.

Euglycaemia


Euglycaemia (American spelling euglycemia) is the state of normal blood sugar (glucose) level.

Eukaryote


Eukaryote is a cellular organism in which the genetic material is contained within a nucleus.

Exacerbate


Exacerbate is a verb meaning to make worse or aggravate.

Exacerbates


Exacerbates is a form of the verb to exacerbate, meaning worsens or aggravates.

Exacerbating


Exacerbating is an adjective pertaining to exacerbation, an aggravation or worsening.

Exacerbation


Exacerbation is a noun meaning an aggravation, worsening, or flare up.

Exacerbations


Exacerbations: plural of exacerbation; aggravations, flares.

Exanthem


Exanthem is a widespread skin rash typically caused by a drug or infection, usually accompanied by systemic symptoms such as fever, malaise, and headache.

Exanthematous


Exanthematous is an adjective pertaining to an exanthem, a widespread rash associated with systemic symptoms often viral or drug in origin.

Excipient


Excipient is an additive to an active drug for medical use. Examples of an exipient include the vehicle or base of a topical preparation, preservative, colouring agent and flavouring.

Excipients


Excipients: plural of excipient; additives to an active drug for medical use including the vehicle or base of a topical preparation, preservatives, colouring agents and flavourings.

Excision


Excision is the surgical removal of an entity such as an organ, tumour, lesion, or foreign body.

Excisional biopsies


Excisional biopsies: plural of excisional biopsy; the complete surgical removal of lesions for diagnosis, treatment, or both.

Excisional biopsy


Excisional biopsy is the complete surgical removal of a lesion for diagnosis, treatment or both.

Excisions


Excisions: plural of excision; surgical removals of tissues, lesions, or organs.

Excoriation


Excoriation, also called a scratch mark, is a loss of epidermis and a portion of the dermis due to scratching. An excoriation may be linear or punctate.

Excoriations


Excoriations: plural of excoriation; scratch marks; the loss of epidermis and some of the dermis due to scratching. Excoriations may be linear or punctate.

Exfoliation


Exfoliation is the process of peeling or shedding of the epidermal stratum corneum. It may occur after skin inflammation, or be induced by chemicals or abrasion.

Exfoliative


Exfoliative is an adjective pertaining to exfoliation, the peeling off in scales or layers.

Exocytosis


Exocytosis is a histological term for the random migration of inflammatory cells, such as lymphocytes, neutrophils, basophils, into the epidermis. Exocytosis is induced by cytokine release in inflammatory processes of the epidermis.

Exogenous


Exogenous is an adjective pertaining to an outside influence or cause. In medicine an exogenous cause for an illness means the cause is not from within, eg, contact dermatitis is an example of an exogenous form of eczema.

Exostosis


Exostosis is a benign growth of new bone out of existing bone.

Exotoxin


Exotoxin is a toxin (poison) produced by and released from a living organism into the surrounds.

Exotoxins


Exotoxins: plural of exotoxin; toxins (poisons) produced by and released from living organisms into the surrounds.

Exposed skin


Exposed skin is skin bared to or influenced by contact with external agents such as sun, chemical allergens, irritants, or physical agents.

Exposed to environment


Exposed to the environment results in potential contact with external agents such as sun, wind, water, irritants and allergens.

Extemporaneous


Extemporaneous is an adjective to describe without prior preparation, being prepared or mixed at the time of dispensing in the case of a medication.

Extemporaneously


Extemporaneously is an adverb meaning carried out without prior preparation; when applied to medicines it means they are prepared or mixed at the time of dispensing.

Extensor


Extensor can be used as an noun or adjective. An extensor is a muscle that extends a joint, and the adjective pertains to these muscles. Extensor aspect overlies extensor muscles.

External auditory canal


External auditory canal connects the outside of the head to the eardrum.

External beam radiotherapy


External beam radiotherapy is the most common form of radiation treatment in which high-energy radiation is directed from outside the body onto an internal cancer.

External-beam radiotherapy


External-beam radiotherapy is the most common form of radiation treatment in which high-energy radiation is directed from outside the body onto an internal cancer.

Extra-articular


Extra-articular is an adjective meaning outside or away from a joint, eg, an extra-articular manifestation.

Extraarticular


Extraarticular is an adjective pertaining to the outside of or away from a joint.

Extracellular matrix


Extracellular matrix is the meshwork or scaffold of molecules outside the cells of a tissue that provides support to those cells. Collagen and elastic fibres are major components of the dermal extracellular matrix.

Extracutaneous


Extracutaneous is an adjective meaning other than or away from the skin, eg, involvement of extracutaneous sites or organs.

Extranodal


Extranodal is an adjective meaning other than lymph nodes, mostly used to mean involvement of other sites with lymphoma.

Extrapulmonary


Extrapulmonary is an adjective meaning to be outside of, not involving, the lungs

Extrapyramidal


Extrapyramidal: is an adjective pertaining to a system that controls motor function.

Extravasate


Extravasate is a verb meaning to leak from a blood vessel into body tissue.

Extravasated


Extravasated is an adjective and past tense verb related to leakage from a blood vessel into body tissue.

Extravasation


Extravasation is the leakage of fluid or cells from a blood vessel into body tissue, eg, extravsation of red blood cells results in a bruise.

Exudate


Exudate is the ooze typically seen in wounds, derived from blood, and composed of protein and blood cells. An exudate can be described as serous, purulent, sanguinous or serosanguinous.

Exudates


Exudates: plural of exudate; oozing and exuded matter from wounds, erosions or ruptured blisters.

F


Facies


Facies is the appearance of the face, which can sometimes be characteristic or aid in the diagnosis of a disorder.

Familial


Familial is an adjective pertaining to family. Familial conditions occur in two or more members of a family and may be genetic or environmental in origin. Genodermatoses may include 'familial' in the name of the condition, eg, familial benign chronic pemphigus.

Fascia


Fascia is collagen-based soft tissue in the body. It is classified as superficial, deep, visceral, and parietal. Fascia encloses and separates compartments and organs, stablises and attaches tissues. The superficial fascia is variably defined as all that lies below the epidermis, or only that part below the subcutaneous fat.

Fascicle


Fascicle is a bundle of fibres or structures such as a bundle of nerve or muscle fibres.

Fascicles


Fascicles: plural of fascicle; when used in biology fascicles are bundles of fibres or structures such as nerves or muscles.

Febrile


Febrile is an adjective pertaining to a fever.

Felon


Felon is a painful abscess in the pulp of a finger or toe.

Ferritin


Ferritin is a body protein that stores iron. Blood ferritin levels are measured to indicate body iron stores.

Fever


Fever is an abnormally high body temperature, usually defined as being over 38 C (100.4 F). It may be accompanied by shivering, headache, and in severe instances, delirium.

Fibril


Fibril is a small fibre or filament.

Fibrils


Fibrils: plural of fibril; small fibres or filaments.

Fibrin


Fibrin is a non-globular insoluble protein formed from fibrinogen, and polymerises to form a blood clot.

Fibrinogen


Fibrinogen is a globulin protein that is the precursor to fibrin. Fibrinogen is cleaved by thrombin to release the fibrin monomer which then polymerises to form a blood clot.

Fibrinoid


Fibrinoid is an adjective meaning fibrin-like. Fibrinoid is used in histology to describe eosinophilic structureless deposits that resemble fibrin, eg, fibrinoid necrosis.

Fibrinoid necrosis


Fibrinoid necrosis is cell death induced by vascular damage from the formation of immune complexes.

Fibroblast


Fibroblast is the most numerous cell type seen in loose connective tissue. In the dermis, fibroblasts produce collagen, elastin, ground substance, and fibronectin.

Fibroblasts


Fibroblasts: plural of fibroblast; the most numerous cell type seen in loose connective tissue. In the dermis fibroblasts produce collagen, elastin, ground substance and fibronectin.

Fibroepithelial


Fibroepithelial is an adjective used to describe the combination of fibrous tissue and epithelium seen on histology.

Fibroepithelioma


Fibroepithelioma is a tumour characterised histologically by fibrous tissue and strands of basal cells in the dermis. It is more correctly called a fibroepithelioma of Pinkus, regarded as being either a rare form of basal cell carcinoma, or a premalignant lesion.

Fibroma


Fibroma describes a family of benign tumours characterised by an increased collagenous stroma. Most present as solitary or multiple dome-shaped skin-coloured papules or nodules.

Fibromas


Fibromas: plural of fibroma; benign tumours consisting mainly of fibrous tissue.

Fibromyalgia


Fibromyalgia is a chronic disease causing stiffness and pain of muscles and joints in the absence of inflammation.

Fibronectin


Fibronectin is a glycoprotein that comes in two forms; circulating (made in the liver) and tissue (made by fibroblasts and endothelial cells). It has many roles particularly in inflammation and wound healing.

Fibroplasia


Fibroplasia is a word used in histology for the growth of fibrous tissue.

Fibrosing


Fibrosing is an adjective and verb pertaining to fibrosis, the formation of fibrous connective tissue.

Fibrosis


Fibrosis is the formation of fibrous connective tissue, either as a normal repair (scarring) or in excess in a pathological process.

Fibrotic


Fibrotic is an adjective describing the presence of excessive fibrous tissue; in the skin this feels leathery, bound-down, thickened or scarred.

Filament


Filament is a thread-like structure or fibre.

Filiform


Filiform is an adjective pertaining to filament, a thread-like structure, eg, filiform wart or filiform papilla of the tongue.

First degree relative


First degree relative: parent, sibling, or child.

FISH


FISH is the acronym for fluorescent in situ (in-situ) hybridisation, a cytogenetic test used to detect chromosomal abnormalities.

Fissure


Fissure is a noun and verb pertaining to a split or crack. In the skin a fissure may present as an erosion or narrow ulceration; the skin may fissure to form a split.

Fissured


Fissured is an adjective and verb pertaining to being split, torn or cracked, eg, fissured skin; the skin fissured.

Fissures


Fissures: plural of fissure; splits, cracks, grooves, clefts.

Fissuring


Fissuring is from the verb to fissure, meaning to split or crack.

Fistula


Fistula is an abnormal passage between two surfaces, two hollow cavities, or a hollow cavity to the body surface.

Fistulae


Fistulae: plural of fistula; abnormal passages between two surfaces, two hollow cavities, or a hollow cavity to the body surface.

Fistulas


Fistulas: plural of fistula; abnormal passages between two surfaces, two hollow cavities, or a hollow cavity to the body surface.

Flaccid


Flaccid is an adjective used to describe hanging loosely, not firm or tense. In dermatology is it typically used to describe a loose blister.

Flexion


Flexion is a bending movement that reduces the angle across a joint.

Flexor


Flexor is an adjective pertaining to flexion, the folding of the body, often at a joint eg, a flexor muscle bends a limb or digit at a joint; a flexor surface is that surface on the inside of the fold or bend. Common usage has flexor as a noun, a muscle that bends a limb at the joint.

Flexural


Flexural is an adjective relating to a bend or fold. In the skin the backs of knees (popliteal fossae), the armpits (axillae), the antecubital (cubital) fossae and the groin are examples of flexural sites. Atopic dermatitis is described as having a flexural distribution on the limbs as it commonly involves the popliteal and antecubital (cubital) fossae.

Flexure


Flexure is a bend or fold, eg, a skin flexure is a skin fold where skin comes in contact across that fold.

Flexures


Flexures: plural of flexure; bends or folds. Skin flexures include under the breasts, armpits, cubital fossae, groin, behind the knees, and describe sites where skin comes in contact across that fold or bend.

Florid


Florid is an adjective used either to describe bright red skin or a fully developed condition, eg, a florid complexion; a florid rash.

Fluctuance


Fluctuance is a noun indicating the presence of fluid in a confined space. Fluctuance is a sign that can be elicted.

Fluctuant


Fluctuant is an adjective pertaining to fluctuance, wave-like rising and falling usually in relation to fluids. In medicine it is used to describe the movement of fluids in the body, eg, describing a mass or tumour as being fluctuant means it is fluid-filled.

Fluorophore


Fluorophore, also called a fluorochrome, is a fluorescent chemical or dye.

Fluorophores


Fluorophores: plural of fluorophore; fluorescent chemicals.

Focal


Focal is an adjective pertaining to focus, relating to or having a focus. It is generally used in medicine to mean being localised to a specific area or tissue.

Follicle


Follicle is a noun with multiple meanings in medicine, including related to the ovary (and follicle stimulating hormone) and lymphocytes (eg, primary cutaneous follicle centre lymphoma). In the skin, a hair follicle is the tubular cavity within which a hair grows.

Follicles


Follicles: plural of follicle; multiple meanings in medicine including relating to structures in the ovaries, lymph nodes, and skin.

Follicular


Follicular is an adjective pertaining to a follicle. In dermatology this usually means a hair follicle, eg, a follicular lesion is located within or around a hair follicle. However in histology follicular also pertains to lymphoid follicles and ovarian follicles.

Formulate


Formulate is a verb meaning to develop a plan, process, or recipe.

Formulation


Formulation is the process of preparing or mixing according to a formula (recipe). Formulation can also be used as the noun for the end product of such a process.

Formulations


Formulations: plural of formulation; the resultant products after preparation or mixing according to formulas (recipes).

Fraction


Fraction is a small part or amount of something whole.

Fractionate


Fractionate is the verb to divide something into smaller parts or amounts.

Fractionated


Fractionated is a verb related to having divided or separated into smaller parts or amounts.

Fragility


Fragility is a noun meaning being easily broken or damaged. Fragility of the skin is the easy bruising and tearing seen especially in the elderly.

Free radical


Free radical is an unstable form of an atom with an unpaired electron, for example, a reactive oxygen species.

Free radicals


Free radicals; plural of free radical; unstable forms of atoms with an unpaired electron, for example, reactive oxygen species. Free radicals can damage cells and tissues.

Frontotemporal


Frontotemporal is an adjective pertaining to the frontal and temporal bones of the skull. For example in surface anatomy, frontotemporal refers to the forehead and temples.

Fundus


Fundus of an organ is the point furthest away from the organ opening or exit, eg, the fundus of the eye is the back of the interior of the eye opposite the pupil.

Fungating


Fungating is an adjective pertaining to a fungus. In dermatology, it is typically used to describe a tumour erupting like a mushroom or toadstool.

Furfuraceous


Furfuraceous is an adjective pertaining to bran. In dermatology, it is used to describe fine skin scale which is bran-like or powdery.

G


Galenical


Galenical is a medicine prepared from plants.

Gamete


Gamete is a haploid cell (having one copy of each chromosome instead of two) for sexual reproduction. In the female this is an ovum (egg) produced in the ovaries, and in the male, sperm produced in the testes (testicles).

Gametes


Gametes: plural of gamete; ova in females and sperm in males for sexual reproduction.

Gammopathies


Gammopathies: plural of gammopathy; conditions characterised by excessive antibodies (gammaglobulins, immunoglobulins) in the blood. It is typically used for monoclonal proliferations of gammaglobulins.

Gammopathy


Gammopathy is a condition characerised by excessive antibodies (gammaglobulins, immunoglobulins) in the blood. It is typically used for a monoclonal proliferation of gammaglobulins.

Ganglia


Ganglia: plural of ganglion; in medicine, there are two types of ganglia: cystic masses associated with tendons or joints; collections of nerve cell bodies as in dorsal root ganglia.

Ganglion


Ganglion derives from the Greek meaning a knot or tumour. In dermatology, a ganglion is a cyst typically associated with a tendon sheath or joint capsule of the hand. In neurology, a ganglion is a group of nerve cell bodies such as a dorsal root ganglion from which shingles emerges.

Ganglions


Ganglions: plural of ganglion; in medicine, there are two types of ganglions: cystic masses associated with tendons or joints; collections of nerve cell bodies as in the dorsal roots.

Gangrene


Gangrene is the local decomposition, necrosis, or putrefaction of a body site or tissue.

Gastroenteritis


Gastroenteritis ('gastro' for short) is inflammation of the stomach and intestinal mucosa. Common usage of gastroenteritis implies an infectious cause, but drugs can also cause gastroenteritis.

Gel


Gel is an aqueous solution thickened with polymers such as methylcellulose for topical application especially on hairy skin. A gel tends to dry on the skin surface.

Gelatinous


Gelatinous is an adjective pertaining to gelatin, having a resemblance to jelly.

Gender


Gender is how a person identifies as male, female, or other, and includes social and cultural factors rather than biological differences.

Gene


Gene is the biological unit of heredity. A gene is encoded in DNA or RNA, and is usually located on a chromosome in the genome.

General anaesthetic


General anaesthetic (American spelling anesthetic) is a mixture of drugs to render painfree, unconsciousness, and sometimes also muscle relaxation if required. General anaesthetic can also be used as an adjective pertaining to the induction of general anaethesia, eg, a general anaesthetic drug.

Generalised


Generalised (American spelling generalized) is an adjective meaning widespread or extensive. A generalised rash is distributed over most of the body surface area. (generalized/widespread/disseminated).

Genes


Genes: plural of gene; the biological units of heredity.

Genetic


Genetic is an adjective pertaining to a gene. Examples include genetic code and genetic disease.

Genetic predisposition


Genetic predisposition is the susceptibility to a disease or condition as a result of inheriting risk factors from one or both parents.

Genital


Genital: adjective pertaining to the external sexual organs.

Genitalia


Genitalia: the external male and female reproductive organs.

Genitourinary


Genitourinary is an adjective pertaining to the interconnected genital and urinary organs of the body. Urogenital can also be used.

Genodermatoses


Genodermatoses: plural of genodermatosis; genetically determined skin conditions.

Genodermatosis


Genodermatosis is a genetically determined skin condition.

Genome


Genome is an organism's complete set of genetic material. It includes all the genes and information required to construct that organism. In eukaryotes the genome is stored in the nucleus. Although a genome in a nucleus is constructed of double-stranded DNA, some viral genomes are made from single- or double-stranded RNA.

Genotype


Genotype is the genetic message at a specific gene locus or the whole genome. The genotype can be sequenced looking for mutations or identifying alleles at a locus. Mutations in the genotype may or may not affect the phenotype.

Genotypes


Genotypes: plural of genotype; genetic messages at specific gene loci or whole genomes.

Genotyping


Genotyping is the process of determining and comparing genetic differences between individuals, using biological assays and nucleic acid sequencing.

Germline


Germline is a noun and adjective pertaining to the genetic material passed to offspring, the next generation. The germline is the cells that produce gametes, the cells by which genetic material is passed between generations. In humans, these gametes are the sperm in men and the ova (eggs) in women. Germline as an adjective describes the genetic material passed from a parent, eg, germline mutation meaning every cell in the offspring carries the same mutation.

Germline mutation


Germline mutation is a gene mutation in the gametes (sperm or ova), so will be passed to offspring. All cells in the offspring will carry the mutation.

Germline mutations


Germline mutations: plural of germline mutation; gene mutations in the gametes (sperm or ova), so will be passed to offspring. All cells in the offspring will carry the mutations.

Gestation


Gestation is the period of time taken for a development. In biology it is typically used to mean the time from conception to birth.

Gestational


Gestational is an adjective pertaining to gestation, the period between conception and birth.

Giant cell


Giant cell is a histological term for an unusually large cell, often with a multiple nuclei.

Giant cells


Giant cells: plural of giant cell; unusually large cells seen on histology, often with multiple nuclei.

Gigantism


Gigantism means abnormal or unusual largeness which may be localised (for example of the vulval labia minora), or generalised due to a pituitary adenoma in childhood.

Gingiva


Gingiva is the gums in the mouth.

Gingivae


Gingivae: plural of gingiva, the gums in the mouth.

Gingival


Gingival is an adjective relating to the gingiva, gums.

Glabella


Glabella is the anatomical term for the skin between the eyebrows above the nose.

Glabrous


Glabrous is an adjective meaning smooth. In dermatology it is used to describe a smooth hairless surface, specifically the palms and soles which lack hair follicles and sebaceous glands.

Gland


Gland is an organ that produces and secretes a substance with a specific function either within the body (endocrine gland) or to the exterior (exocrine gland).

Glands


Glands: plural of gland; organs that produce and secrete substances with specific functions in the body.

Glandular


Glandular is an adjective pertaining to a gland(s), organs that produce and secrete substances with specific functions in the body.

Glaucoma


Glaucoma is increased pressure in the eye. It may be classified as open-angle (excessive intraocular fluid production) or closed-angle (an inability to drain the fluid normally). Glaucoma can result in optic nerve damage and blindness.

Globular


Globular is an adjective pertaining to a globule, a small round structure or particle.

Globule


Globule is a small round structure or particle.

Globules


Globules: plural of globule; small round structures or particles.

Glossitis


Glossitis is inflammation of the tongue.

Glucocorticoid


Glucocorticoid, also called a glucocorticosteroid, is a family of steroid hormones produced in the cortex of the adrenal gland, with effects mainly on carbohydrate metabolism, eg, cortisol. Topical, inhaled or systemic treatments may include a synthesised glucocorticoid (cortisone).

Glucocorticoids


Glucocorticoids: plural of glucocorticoid; steroid hormones produced in the cortex of the adrenal gland, with effects mainly on carbohydrate metabolism, eg, cortisol. Glucocorticoids can also be synthesised for topical, inhaled or systemic treatment.

Glucocorticosteroid


Glucocorticosteroid, also called a glucocorticoid, is a (cortico)steroid hormone produced in the cortex of the adrenal gland, with effects mainly on carbohydrate metabolism, eg, cortisol. Topical, inhaled or systemic treatments may include a synthesised glucocorticosteroid (cortisone).

Glucocorticosteroids


Glucocorticosteroids: plural of glucocorticosteroid; steroid hormones produced in the cortex of the adrenal gland, with effects mainly on carbohydrate metabolism, eg, cortisol. Glucocorticosteroids can also be synthesised for topical, inhaled or systemic treatment.

Glucose


Glucose, also called dextrose, is a simple sugar molecule found in plants and animals used as a source of energy by living cells; it is the main sugar found in the bloodstream and it is the glucose level that is meant by 'blood sugar'.

Gluteal


Gluteal is an adjective pertaining to gluteus, the buttocks.

Gluteus


Gluteus is a buttock muscle, of which there are three specfic types.

Glycoprotein


Glycoprotein is a protein with a carbohydrate component.

Glycoproteins


Glycoproteins: plural of glycoprotein; proteins with a carbohydrate component.

Granular


Granular is an adjective pertaining to granules, small intracellular particles seen on microscopy of tissue.

Granular layer


Granular layer of the epidermis (stratum granulosum) is characterised by flattened cells filled with dark granules containing keratohyaline protein.

Granulation tissue


Granulation tissue is a mass of new capillaries, fibroblasts, and inflammatory cells in a healing wound.

Granule


Granule is a tiny quantity of a solid substance. In microscopy it usually refers to a small intracellular particle.

Granules


Granules: plural of granule; small intracellular particles.

Granulocyte


Granulocyte is a type of white blood cell (leukocyte) with a cytoplasm filled with microscopic granules containing enzymes and other proteins important in innate immunity. Neutrophils, basophils and eosinophils are the three most common forms of granulocyte in the blood.

Granulocytes


Granulocytes: plural of granulocyte; white blood cells with cytoplasmic granules.

Granuloma


Granuloma is a histological term for a chronic inflammatory pattern characterised by the localised aggregation of histiocytes with or without other inflammatory cells, with or without necrosis, with or without vasculitis, with or without calcification, with or without foreign bodies. A granuloma may be due to infection, chronic inflammatory disease, or reaction to foreign material.

Granulomas


Granulomas: plural of granuloma; a histological term for a chronic inflammatory pattern characterised by localised aggregations of histiocytes with or without other inflammatory cells, with or without necrosis, with or without vasculitis, with or without calcification, with or without foreign bodies. Granulomas may be due to infection, chronic inflammatory disease, or reactions to foreign material.

Granulomatous


Granulomatous is an adjective pertaining to granulomas, a type of chronic inflammation characterised by histiocytes.

Grenz zone


Grenz zone is a histological term for an apparently uninvolved area (zone) of papillary dermis separating the epidermis from an inflammatory or tumour cell infiltrate in the dermis.

Ground substance


Ground substance is the gel component of the dermis. It contains hyaluronic acid, dermatan sulphate, chondroitin-6-sulphate, anionic polysaccharides, and glycosaminoglycans. It does not include the fibres such as collagen and elastin, or cells.

Grouped


Grouped is an adjective pertaining to a cluster. A cluster of lesions may be described as grouped.

Growth factor


Growth factor is a protein involved in the regulation of cellular growth, proliferation, and differentiation under controlled conditions, eg, epidermal growth factor.

Growth factors


Growth factors: plural of growth factor; proteins involved in the regulation of cellular growth, proliferation, and differentiation under controlled conditions.

Gustatory


Gustatory is an adjective pertaining to taste.

Guttate


Gutatte means drop-like, a pattern resembling tear-drops or rain-drops.

Gynaecomastia


Gynaecomastia (American spelling gynecomastia) is enlarged breast tissue in a male.

Gyrate


Gyrate is an adjective meaning spiral-like or rotating. In dermatology it is used to describe a pattern that is convoluting, winding, or coiled.

Gyrate rash


Gyrate rash is arranged in circles or spirals.

Gyrate rashes


Gyrate rashes: plural of gyrate rash; are arranged in circles or spirals.

H


Haemagglutination


Haemagglutination (American spelling hemagglutination) is the agglutination (process of clumping) of red blood cells. As this can be seen without needing a microscope it is used in laboratories for blood typing, and to detect antibodies, viruses, or other infectious micro-organisms.

Haemangioma


Haemangioma (American spelling; hemangioma) is a benign proliferative blood vessel tumour, often developmental in origin.

Haemangiomas


Haemangiomas: plural of haemangioma; (American spelling hemangiomas/hemangioma); benign blood vessel tumours often developmental in origin.

Haemarthrosis


Haemarthrosis: bleeding into a joint.

Haematocrit


Haematocrit (American spelling hematocrit) is defined as the ratio of the volume of red blood cells to the total volume of blood. It is measured by separating red blood cells from plasma by centrifugation.

Haematogenous


Haematogenous (American spelling hematogenous) is an adjective pertaining to blood, its production, constituents, dissemination, or derivation, eg, haematogenous spread of a cancer means cancer cells have been spread via the bloodstream.

Haematological


Haematological (American spelling hematological) is an adjective pertaining to haematology, the blood system.

Haematologist


Haematologist (American spelling hematologist) is a medical specialist in the care and study of blood disorders.

Haematology


Haematology (American spelling hematology) is the study of blood disorders.

Haematoma


Haematoma (American spelling hematoma) is a localised swelling due to a collection of blood in or under the skin.

Haematomas


Haematomas: plural of haematoma (American spelling hematomas/hematoma); localised swellings due to collections of blood in or under the skin.

Haemoglobin


Haemoglobin (American spelling hemoglobin) is a family of iron-containing proteins in red blood cells.

Haemoglobins


Haemoglobins: plural of haemoglobin (American spelling hemoglobins/hemoglobin); iron-containing proteins in red blood cells.

Haemolysis


Haemolysis (American spelling hemolysis) is the rupture or destruction of red blood cells.

Haemolytic


Haemolytic (American spelling hemolytic) is an adjective pertaining to the rupture or destruction of red blood cells.

Haemophagocytic syndrome


Haemophagocytic syndrome: is defined by the triad of fever, enlarged spleen, and cytopenias.

Haemophagocytosis


Haemophagocytosis (hemophagocytosis): the swallowing (phagocytosis) of intact red and white blood cells, and platelets (haemopoeitic cells) by histiocytes in the bone marrow or other tissues.

Haemophilia


Haemophilia (American spelling hemophilia) is a group of genetic conditions characterised by delayed clotting of blood due to an absent or defective clotting factor.

Haemorrhage


Haemorrhage (American spelling hemorrhage) is a noun and verb pertaining to a bleed or to bleed.

Haemorrhages


Haemorrhages: plural of haemorrhage (American spelling hemorrhages); as a noun means loss of blood from a blood vessel; as a verb means to be losing blood.

Haemorrhagic


Haemorrhagic (American spelling hemorrhagic) is an adjective pertaining to haemorrhage, a bleed, eg, a haemorrhagic bulla is a blood-filled blister.

Haemosiderin


Haemosiderin (American spelling hemosiderin) is the brown iron-containing pigment derived from blood.

Haemosiderosis


Haemosiderosis (American spelling hemosiderosis) is the accumulation of haemosiderin, a form of iron, in tissues usually as a result of bleeding.

Haemostasis


Haemostasis (American spelling hemostasis) is the process that stops blood flow in bleeding or haemorrhage. This can be achieved surgically during a procedure using sutures or diathermy.

Hair


Hair is a specialised epidermal product of the pilosebaceous structure, made of keratin. Terminal hair is found on the scalp; vellus hair on body surface; lanugo hair on the fetus.

Hair cycle


Hair cycle consists of a growth phase (anagen); a short involutional phase (catagen); a resting phase (telogen).

Hair pull test


Hair pull test is used for assessing a patient complaining of hair loss. If more than 10% of hairs in a pulled bundle are removed, the result is considered abnormal (positive). None, one or two hairs removed when gently tugging on a bundle of 50-60 hairs is considered normal.

Hair-pull test


Hair-pull test is used for assessing a patient complaining of hair loss. If more than 10% of hairs in a pulled bundle are removed, the result is considered abnormal (positive).

Hamartoma


Hamartoma is a benign overgrowth of a mature cell type normal to the site or organ. In the skin a hamartoma often presents as a birthmark (congenital naevus), but may first develop, appear, or be noticed in adult life (acquired). Examples include naevus sebaceous, follicular hamartoma, and chondroid syringoma.

Hamartomas


Hamartomas: plural of hamartoma; benign overgrowths of a mature cell type normal to the site or organ. They may be congenital or acquired.

Haploid


Haploid is an adjective describing a cell with only one set of chromosomes, as is typically seen in gametes (ova and sperm).

Heliotrope


Heliotrope is a purple flowering plant, and is used to describe a pink-purple colour reminiscent of the flower.

Helminth


Helminth is a parasitic worm. Examples of a helminth include a tapeworm, liver fluke, roundworm, and leech.

Helminths


Helminths; plural of helminth; parasitic worms including tapeworms, liver flukes, roundworms, and leeches.

Hemidesmosome


Hemidesmosome is a structure in the basemement-membrane zone, made by the epidermal basal keratinocytes, and involved in sticking the basal keratinocytes to the dermis.

Hemidesmosomes


Hemidesmosomes: plural of hemidesmosome; structures in the basemement-membrane zone, made by the epidermal basal keratinocytes and involved in sticking the basal keratinocytes to the dermis.

Hemifacial


Hemifacial is an adjective pertaining to half the face.

Hepatic


Hepatic is an adjective relating to the liver.

Hepatitis


Hepatitis is inflammation of the liver.

Hepatocyte


Hepatocyte is the main functioning cell in the liver.

Hepatocytes


Hepatocytes: plural of hepatocyte; the main functioning cells in the liver.

Hepatomegaly


Hepatomegaly is enlargement of the liver.

Hepatosplenomegaly


Hepatosplenomegaly is abnormal enlargement of both the liver and spleen.

Hepatotoxic


Hepatotoxic is an adjective pertaining to liver-damaging properties or effects.

Hepatotoxicity


Hepatotoxicity is a toxic hepatitis, a state of liver damage due to liver-damaging chemicals. Hepatotoxicity is also a measure of the degree a chemical will cause liver damage, eg, the hepatoxicity of a drug.

Hepatotoxin


Hepatotoxin is a chemical that damages the liver.

Hepatotoxins


Hepatotoxins: plural of hepatoxin; chemicals that damage the liver.

Hereditary


Hereditary is an adjective pertaining to inheritance. In medicine, it is used to describe a genetic (inherited) mutation or condition.

Herpetiform


Herpetiform is an adjective meaning to resemble herpes, so is used to describe clustered vesicles and does not imply a viral origin.

Herpetiformis


Herpetiformis, see also herpetiform, describes grouped or clustered vesicles or papules, resembling herpes

Heterogeneous


Heterogeneous is an adjective pertaining to having diverse or various causes or content.

Heterogenous


Heterogenous refers to a structure having a foreign origin.

Heterozygosity


Heterozygosity is the noun meaning the two copies of a specific gene are different alleles, ie, heterozygosity at a gene locus.

Heterozygous


Heterozygous is an adjective pertaining to heterozygosity, the two copies of a gene are different alleles, eg, in an autosomal dominant condition the relevant gene is heterozygous.

Hilar lymphadenopathy


Hilar lymphadenopathy is enlarged mediastinal lymph nodes usually detected on chest X-ray.

Histamine


Histamine, 2-[4-imadazolyl]ethylamine, is stored in the granules of mast cells and basophils, and released rapidly via an IgE-mediated mechanism during hypersensitivity and inflammation. Local histamine release causes capillary vasodilation and plasma leakage. In anaphylaxis large amounts of histamine are released with systemic effects on smooth muscle and blood pressure.

Histiocyte


Histiocyte is a tissue macrophage; a phagocytic cell important in granuloma formation.

Histiocytes


Histiocytes: plural of histiocyte; tissue macrophages. Histiocytes are important in the formation of granulomas and can fuse to form multinucleated giant cells.

Histiocytic


Histiocytic is an adjective pertaining to histiocytes, phagocytic tissue cells.

Histiocytosis


Histiocytosis is a group of diseases characterised by too many histiocytes in the skin and other organs. There are two main types of histiocytosis: Langerhans cell histiocytosis and non-Langerhans histiocytosis, which are further subdivided.

Histological


Histological is an adjective pertaining to histology, the study of the microscopic appearance of normal and abnormal biological tissues.

Histologically


Histologically is an adverb pertaining to histology, the study of the microscopic appearance of biological tissue.

Histology


Histology is the study of the microscopic appearance of normal and abnormal biological tissues.

Histopathological


Histopathological is an adjective pertaining to histopathology, the science of the microscopic assessment of diseased, abnormal tissue.

Histopathologically


Histopathologically is an adverb pertaining to histopathology, the science of the microscopic assessment of diseased and abnormal tissue.

Histopathology


Histopathology is the study of the microscopic appearance of biological tissues to help in the diagnosis of disease.

HIV


HIV is an acronym for human immunodeficiency virus.

HLA


HLA is an acronym for human leukocyte antigen(s), a complex of proteins expressed on human cells that help the immune system to distinguish self. HLA is the human version of the Major Histocompatibility Complex (MHC). HLA typing is also known as tissue typing, and is important for matching organ donors and recipients. Specific HLA types can be associated with disease susceptibility risk.

Homeostasis


Homeostasis is the state of equilibrium in the body created by its self-regulating processes. Illness, injury and chronic medical conditions can disrupt homeostasis.

Homogeneous


Homogeneous is an adjective to describe being uniform throughout, all the same.

Homogenous


Homogenous describes a thing or things as being the same throughout.

Homozygosity


Homozygosity is a noun meaning the two copies of a specific gene are the same allele, ie homozygosity at a gene locus.

Homozygous


Homozygous is an adjective pertaining to homozygosity, identical alleles of a specific gene, eg, an autosomal recessive condition requires the relevant gene to be homozygous.

Horn


Horn is a hard structure composed predominantly of bone which may have an epidermal coating. However a cutaneous horn in human skin is an accumulation of hard keratin attached to the skin surface.

Horner Syndrome


Horner syndrome is a sympathetic nerve disorder defined by a classic triad of symptoms usually involving only one side of the face: a small unresponsive pupil; droopy upper eyelid; loss of facial sweating.

Horny layer


Horny layer of the epidermis (stratum corneum) consists of stacks of keratinised dead cells without nuclei. The top layer of these cells loosens and falls off.

Host


Host, in biology, is the cell, animal, or plant on which a parasitic organism lives. Host can also be used to mean self as in a host or self antigen being recognised as foreign.

Hosts


Hosts: plural of host; in biology the cells, animals, or plants on which parasitic organisms live.

Human leukocyte antigen


Human leukocyte antigen (acronym HLA) is a complex of proteins expressed on human cells that help the immune system to distinguish self from foreign.

Humectant


Humectant is a substance that attracts moisture. Naturally occurring humectants are found in the dermis. A humectant may be used as a skin moisturiser and examples include glycerine, sorbitol, urea, hyaluronic acid and alpha-hydroxy acids.

Humectants


Humectants: plural of humectant; substances that attract moisture. Naturally occurring humectants can be found in the dermis. Humectants may be used as skin moisturisers and examples include glycerine, sorbitol, urea, hyaluronic acid and alpha-hydroxy acids.

Humid


Humid is an adjective pertaining to humidity, the water content of air; humid air has a high moisture content.

Humidity


Humidity is a measure of the moisture content of air.

Hyaline


Hyaline is eosinophilic amorphous material resulting from degeneration of collagen in the superficial dermis, a word used in dermatopathology.

Hyalinisation


Hyalinisation is the process of forming hyaline in the dermis resulting in a ground-glass appearance, a word used in dermatopathology.

Hyalinised


Hyalinised is an adjective pertaining to hyaline; a ground-glass appearance due to collagen degeneration.

Hydrocephalus


Hydrocephalus is an excess of cerebrospinal fluid in the brain.

Hydrophilic


Hydrophilic is an adjective pertaining to the ability to combine with or dissolve in water.

Hydrophobic


Hydrophobic is an adjective pertaining to the inability or failure to mix with water.

Hydrostatic pressure


Hydrostatic pressure: is the pressure exerted by a fluid, a water pushing force.

Hyperaesthesia


Hyperaesthesia (American spelling hyperesthesia) is an abnormal increase in skin sensitivity to light touch, usually with a neurological cause.

Hyperalgesia


Hyperalgesia is an abnormal increase in sensitivity to a painful stimulus, usually with a neurological cause.

Hyperbaric


Hyperbaric is an adjective pertaining to increased gas pressure.

Hypercalcaemia


Hypercalcaemia (American spelling hypercalcemia) means the calcium level in the blood is higher than normal.

Hypercalciuria


Hypercalciuria means the calcium level in the urine is higher than normal.

Hypercholesterolaemia


Hypercholesterolaemia (American spelling hypercholesterolemia) is a higher than healthy blood level of cholesterol, a high cholesterol blood level.

Hyperchromatic


Hyperchromatic is an adjective pertaining to increased chromatin, the condensed DNA and protein in the cell nucleus. It is used in histology to describe darker than usual staining of the cell nucleus, eg, hyperchromatic nuclei in skin malignancies.

Hyperchromatism


Hyperchromatism is increased nuclear staining due to clumping of the nuclear chromatin, a word used in histopathology.

Hypercoagulability


Hypercoagulability is the tendency for blood to clot more easily than normal.

Hypercoagulable


Hypercoagulable is an adjective pertaining hypercoagulability, tendency toward increased clotting of blood.

Hyperglycaemia


Hyperglycaemia (American spelling hyperglycemia) is high blood glucose (sugar) level.

Hypergranulosis


Hypergranulosis is an increased numbers of intracellular granules within the granular layer of the epidermis compared to normal, a word used in dermatopathology.

Hyperhidrosis


Hyperhidrosis is excessive sweating and be localised to one body site, eg, palms, or  generalised, affecting the whole body.

Hyperkalaemia


Hyperkalaemia (American spelling hyperkalemia) is a higher than normal potassium level in the blood.

Hyperkeratosis


Hyperkeratosis is a thickening of the stratum corneum, the outermost layer of the skin.

Hyperkeratotic


Hyperkeratotic is an adjective pertaining to hyperkeratosis, thickening of the stratum corneum, the outermost layer of the skin.

Hyperlipidaemia


Hyperlipidaemia (American spelling hyperlipidemia) is a higher than normal blood level of one or more of the lipids (fats) such as cholesterol or triglycerides.

Hyperpigmentation


Hyperpigmentation is a darker colour than normal for that person or site, due to increased pigment. It can be localised or generalised.

Hyperpigmented


Hyperpigmented is an adjective pertaining to hyperpigmentation, increased colour due to pigment. Hyperpigmented skin is darker than normal for that site, individual or population.

Hyperplasia


Hyperplasia is the enlargement of a tissue by an increase in cell numbers.

Hyperplastic


Hyperplastic is an adjective pertaining to hyperplasia; enlargement due to increased cell numbers.

Hyperproliferation


Hyperproliferation is increased proliferation (replication) of cells.

Hyperproliferative


Hyperproliferative is an adjective pertaining to hyperproliferation, increased replication of cells.

Hyperproteinaemia


Hyperproteinaemia: abnormally high protein level in the blood.

Hypersensitivity


Hypersensitivity is an exaggerated immune reaction to an allergen or antigen following sensitisation. There are several types of hypersensitivity reaction: type I (immediate); type II (cytotoxic); type III (immune complex); type IV (delayed, T-cell mediated). Non-allergic hypersensitivity is a pseudoallergy as it does not involve the immune system.

Hypertension


Hypertension is high blood pressure.

Hypertensive


Hypertensive is an adjective pertaining to hypertension, high blood pressure.

Hyperthyroid


Hyperthyroid is an adjective pertaining to hyperthyroidism, overproduction of thyroid hormone.

Hyperthyroidism


Hyperthyroidism is the overproduction of thyroid hormone by the thyroid gland.

Hypertonic


Hypertonic is an adjective with several meanings. Hypertonic pertains to having a comparatively high osmotic pressure (eg, a hypertonic solution); and pertains to hypertonia, increased muscle tone (eg, hypertonic bladder).

Hypertrichosis


Hypertrichosis is excessive hair growth, not in the patterned distribution of hirsutism. Hypertrichosis may be localised or generalised.

Hypertriglyceridaemia


Hypertriglyceridaemia (American spelling hypertriglyceridemia) is a higher than healthy level of triglyceride in the blood.

Hypertrophic


Hypertrophic is an adjective pertaining to hypertrophy, excessive growth, overgrowth.

Hypertrophied


Hypertrophied is an adjective pertaining to hypertrophy, thickening or enlargement of a part due to enlargement of the cells and not due to an increased number of cells.

Hypertrophy


Hypertrophy is excessive growth or enlargement.

Hyperviscosity


Hyperviscosity is an adjective pertaining to increased viscosity. In medicine it describes thick, sticky blood with poor flow due to increased or abnormal cells or proteins.

Hyphae


Hyphae, plural of hypha, long filaments of fungi that form the mycelium.

Hyphema


Hyphema: blood between the cornea and iris, the anterior chamber of the eye.

Hypogeusia


Hypogeusia means decreased sense of taste.

Hypoglycaemia


Hypoglycaemia (American spelling hypoglycemia) is a low blood glucose (sugar) level.

Hypoglycaemic


Hypoglycaemic is an adjective pertaining to hypoglycaemia, low blood glucose (sugar).

Hypogonadism


Hypogonadism is underactivity or inadequate function of the gonads (reproductive glands) leading to impaired production of germ cells and sex hormones.

Hypohidrosis


Hypohidrosis is decreased sweating.

Hypohidrotic


Hypohidrotic is an adjective pertaining to hypohidrosis, reduced sweating.

Hypomelanosis


Hypomelanosis means reduced or absent melanin in the epidermis of the skin.

Hypomelanotic


Hypomelanotic is an adjective pertaining to hypomelanosis, localised melanin pigment reduction or loss.

Hypomorphic


Hypomorphic is an adjective pertaining to a gene mutation that results in reduced (but not lost) function.

Hyponychium


Hyponychium is the skin under the distal free end of the nail plate.

Hypophysitis


Hypophysitis is inflammation of the pituitary gland or stalk.

Hypopigmentation


Hypopigmentation is colour that is paler than normal for that person or site, due to reduced pigment. It may be generalised or localised.

Hypopigmented


Hypopigmented is an adjective pertaining to hypopigmmentation, paler colour due to reduced pigment. Hypopigmented skin is lighter in colour compared to normal for that site, individual, or population.

Hypoproteinaemia


Hypoproteinaemia: low protein level in the blood.

Hypotension


Hypotension is low blood pressure.

Hypotensive


Hypotensive is an adjective pertaining to hypotension, low blood pressure.

Hypothalamic


Hypothalamic is an adjective pertaining to the hypothalamus; that part of the brain which coordinates the autonomic nervous system and controls pituitary gland activity.

Hypothalamus


Hypothalamus is the part of the brain that coordinates the autonomic nervous system and controls pituitary gland activity.

Hypothermia


Hypothermia is a low body temperature. It happens when the body is losing more heat than it can make. In dermatology, hypothermia may complicate conditions associated with extensive skin redness as in erythroderma. Hypothermia can be a medical emergency.

Hypothermic


Hypothermic is an adjective pertaining to hypothermia, a low body temperature.

Hypothyroid


Hypothyroid is an adjective pertaining to hypothyroidism, underproduction or insufficient thyroid hormone.

Hypothyroidism


Hypothyroidism is insufficient circulating thyroid hormone resulting from underproduction by the thyroid gland.

Hypotonia


Hypotonia is decreased muscle tone, a state in which the muscle is always relaxed.

Hypotonic


Hypotonic is an adjective with several meanings. Hypotonic pertains to having a comparatively low osmotic pressure (eg, a hypotonic solution); pertaining to hypotonia, decreased muscle tone.

Hypotrichosis


Hypotrichosis is a relative lack of hair growth, often congenital or genetic in origin.

Hypoxaemia


Hypoxaemia: abnormally low blood oxygen level.

Hypoxia


Hypoxia is when inadequate oxygen reaches tissues.

I


Iatrogenic


Iatrogenic is an adjective describing an event or outcome as a result of a doctor's action. In dermatology, an example of an iatrogenic illness would be a rash due to prescription of a medicine.

Ichthyoses


Ichthyoses: plural of ichthyosis; fish-scale skin.

Ichthyosis


Ichthyosis is skin with a fish-scale-like surface. There are many types of ichthyosis with both genetic and acquired forms.

Icteric


Icteric is an adjective pertaining to jaundice (icterus).

Idiopathic


Idiopathic means the cause or reason is no known.

IgA


IgA: immunoglobulin A; a class of antibody forming the first line of defence against infection.

IgE


IgE: immunoglobulin E; a class of antibody involved in defence against parasites and some forms of allergies.

IgG


IgG: immunoglobulin G; a class of antibody, the most common of the circulating immunoglobulin types.

IgM


IgM: immunoglobulin M; a class of antibody, the first to appear in response to an infection. 

Immnuosuppressive


Immunosuppressive means a particular condition or treatment suppresses or reduces the immune system.

Immobile


Immobile is an adjective pertaining to immobility, being motionless, unable to move.

Immobility


Immobility is the state of not moving.

Immune cell


Immune cell is a involved in innate or acquired immunity. In the skin many types of immune cell can be identified including Langerhans cell, lymphocyte, neutrophil, monocyte and mast cell.

Immune cells


Immune cells: plural of immune cell; in the skin these include Langerhans cells, lymphocytes, neutrophils, monocytes (histiocytes and activated macrophages), and mast cells. Immune cells are recruited to the skin in great numbers to heal wounds and fight infection.

Immune compromised


Immune compromised is an adjective pertaining to an impaired or weakened immune system for any reason, resulting in a reduced ability to resist or fight infection. This may be due to genetic disease, illness, or medications.

Immune suppression


Immune suppression is the impairment and general dampening of the immune response by an external agent such as a medication or infection.

Immune therapy


Immune therapy is a medical treatment that alters the immune system by causing induction, enhancement, or suppression of an immune response.

Immune-compromised


Immune-compromised is an adjective pertaining to an impaired or weakened immune system for any reason, resulting in a reduced ability to resist or fight infection. Causes include genetic disease, illness, or medications.

Immunobullous


Immunobullous is an adjective pertaining to blisters caused by an autoantibody-mediated immune reaction.

Immunocompromised


Immunocompromised is an adjective pertaining to an impaired or weakened immune system for any reason, resulting in a reduced ability to resist or fight infection. Causes may include a genetic disease, illness, or medications.

Immunofluorescence


Immunofluorescence (acronym IF) is a laboratory test that uses a fluorescent marker attached to a protein to detect or identify antibodies or antigens on cell surfaces, and other cell and tissue components. It may be direct (DIF) or indirect (IIF).

Immunogen


Immunogen, also known as an antigen, is a substance or molecule capable of causing an immune response in the body.

Immunogens


Immunogens: plural of immunogen; antigens.

Immunoglobulin


Immunoglobulin (acronym Ig) is a specific type of globulin protein produced by activated B cells (plasma cells) and involved in the immune response. There are five types of immunoglobulin: A, D, E, G and M.

Immunoglobulins


Immunoglobulins: plural of immunoglobulin; a specific type of globulin protein produced by B cells and involved in the immune response.

Immunohistochemistry


Immunohistochemistry is a laboratory test performed on either fresh or formalin-fixed tissue to identify specific cell types by looking for cell-markers using antibodies with fluorescent or coloured dyes attached.

Immunological


Immunological is an adjective pertaining to the immune system.

Immunology


Immunology is the study of the immune system; how the body protects itself from diseases and infections, and when it can go wrong.

Immunomodulation


Immunomodulation is the process of regulating or modifying an immune function.

Immunomodulatory


Immunomodulatory is an adjective pertaining to immunomodulation, the process or agent that regulates or modifies an immune function.

Immunoophenotyping


Immunophenotyping is the identification of specific antigens or markers expressed by a cell, using antibodies (immunoglobulins).

Immunopathogenesis


Immunopathogenesis is the process of disease development involving the immune system.

Immunosuppressed


Immunosuppressed is an adjective pertaining to immunosuppression; the impairment or general dampening of the immune response by an external agent such as a medication or infection.

Immunosuppression


Immunosuppression is the impairment or general dampening of the immune response by an external agent such as a medication or infection.

Immunosuppressive


Immunosuppressive is an adjective pertaining to immunosuppression; the general dampening of the immune response by an external agent usually a medication (drug). Common usage also has immunosuppressive as a noun ie an immunosuppressive (drug).

Immunotherapies


Immunotherapies: plural of immunotherapy; medical treatments that alter the immune system by causing induction, enhancement or suppression of an immune response.

Impetiginisation


Impetiginisation (American spelling impetiginization) is the process of secondary bacterial infection of a rash.

Impetiginised


Impetiginised (American spelling impetiginized) is an adjective pertaining to impetiginisation, the process of secondary bacterial infection of a rash.

In situ


In situ means 'in place'; an adjective and noun pertaining to being confined to the site of origin or placement, eg, pre-invasive phase as in melanoma in situ; the dressing remains in situ.

In utero


In utero means in the uterus (womb), before birth.

In-situ


In-situ means 'in place'; an adjective and noun pertaining to being confined to the site of origin or placement, eg, pre-invasive phase as in melanoma In-situ; the dressing remains in-situ.

Incidence


Incidence is the measure of the likelihood that a condition will occur within a population over time; incidence is the number of new cases of a specific condition occurring in a defined timeframe.

Incision


Incision is a surgical cut into tissue, such as the skin.

Incisional


Incisional is an adjective pertaining to an incision; a surgical cut.

Incisional biopsies


Incisional biopsies: plural of incisional biopsy; surgical procedures to sample selected areas of skin lesion(s) for histopathology.

Incisional biopsy


Incisional biopsy is the surgical procedure to sample a selected portion of a lesion for evaluation by a pathologist.

Incisions


Incisions: plural of incision; surgical cuts into tissue, such as the skin.

Inclusion


Inclusion can be the process of including, or an included thing. In a cell an inclusion may be within the nucleus or cytoplasm.

Inclusions


Inclusions: plural of inclusion; things included or within. In cells, inclusions seen in the cytoplasm and nucleus are usually normal transient constituents such as glycogen or lipid granules or droplets.

Incubate


Incubate is a verb meaning to develop, eg, to incubate an infection, an egg, or bacteria.

Incubation


Incubation is the process of developing. It can be the time between exposure to an infection and the development of symptom or signs, ie, the incubation of an infection. Bacterial incubation in the laboratory allows time for development of colonies for identification or study. The incubation of eggs allows the embryo to develop until hatching.

Indolent


Indolent is an adjective per5aining to indolence, lazy and sluggish. In medicine, indolent is used to describe a condition that is slow to develop, progress, or heal.

Inducible


Inducible is an adjective pertaining to induction, the creation or activation by an external stimulus.

Induction


Induction is the process of inducing, creating, activating.

Induction therapy


Induction therapy is the first treatment of a condition, aiming for remission or increasing efficacy of subsequent therapies. It is most commonly used in cancer treatment.

Induction treatment


Induction treatment is the first treatment of a condition, aiming for remission or increasing efficacy of subsequent therapies. It is most commonly used in cancer treatment.

Induction treatments


Induction treatments: plural of induction treatment; first treatments of conditions aiming for remission or increasing efficacy of subsequent therapy.

Indurated


Indurated is an adjective pertaining to induration, and abnormal hardening.

Induration


Induration is an abnormal hardening. Induration of skin may be due to oedema or fibrosis, and feels firm and thickened.

Infarct


Infarct is localised tissue death due to an interruption of blood supply.

Infarction


Infarction is the result of an interrupted blood supply, and in the skin presents as black areas of necrotic (dead) tissue or dry gangrene.

Infarcts


Infarcts: plural of infarct; localised tissue death due to interrupted blood supply. In the skin this may result in black areas of necrotic (dead) tissue or dry gangrene.

Infection


Infection is an illness caused by a pathogenic micro-organism such as a virus, bacterium, fungus, or parasite.

Infections


Infections: plural of infection; illnesses caused by pathogenic micro-organisms such as viruses, bacteria, fungi, or parasites.

Inferior


Inferior is an adjective pertaining to being below or less effective. In dermatology an inferior location means on the lower surface of a body part or closer to the feet. Drug A was inferior to drug B in the clinical trial.

Infest


Infest: verb to invade or live on as a parasite or insect.

Infestation


Infestation is an invasion by a parasite or insect, eg, scabies mite, human flea.

Infested


Infested: an adjective or verb pertaining to being invaded or lived upon by an insect or parasite.

Infiltrate


Infiltrate can be used as a verb or noun. The verb means to enter, permeate, or pass through. The noun refers to an accumulation of cells in tissue. Neutrophils infiltrate the skin resulting in an infiltrate of neutrophils.

Infiltrates


Infiltrates: plural of infiltrate (noun); abnormal accumulations of cells in tissue such as the skin. Infiltrates is also the present tense of the verb to enter, permeate, or pass through.

Infiltration


Infiltration is the process of entering, permeating, or passing through.

Infiltrative


Infiltrative is an adjective pertaining to an infiltrate or infiltration, an accumulation.

Inflammasome


Inflammasome is an intracellular complex comprising a receptor, a caspase-1 enzyme, and an apoptosis-associated speck-like protein. It is part of the innate immune system involved in binding and eliminating microbes.

Inflammasomes


Inflammasomes; plural of inflammasome: intracellular complexes involved in the binding and elimination of microbes.

Inflammation


Inflammation is a tissue response to injury or disease. In the skin it is recognised by a combination of redness, swelling, heat, pain, or itch.

Inflammatory


Inflammatory is an adjective pertaining to inflammation, an immune reaction causing redness, swelling, pain, and heat.

Inflammatory mediator


Inflammatory mediator is a messenger molecule that promotes inflammation by effects on blood vessels and inflammatory cells.

Inflammatory mediators


Inflammatory mediators: plural of inflammatory mediator; messenger molecules that promote inflammation by effects on blood vessels or inflammatory cells.

Infundibular


Infundibular is an adjective pertaining to infundibulum, a funnel shaped passage.

Infundibulum


Infundibulum is a funnel shaped passage. In the skin the hair follicle infundibulum is that part of the follicle above the level of the insertion of the sebaceous gland.

Ingest


Ingest is a verb meaning to take in or swallow.

Ingested


Ingested is the past tense of the verb to ingest, meaning to have taken in or swallowed.

Ingestion


Ingestion means the process of taking in or swallowing of food, drink, or another substance.

Inguinal


Inguinal is an adjective pertaining to the groin (inguinal fold).

Inguinal region


inguinal region is the groin.

Inhalant


Inhalant is a medication that has been breathed in (inhaled) to be absorbed through the respiratory mucous membranes.

Inhalants


Inhalants: plural of inhalant; inhaled medications.

Inhalation


Inhalation is the process (act) of breathing in. Common usage makes Inhalation a noun for an inhaled medication.

Inhibit


Inhibit is a verb meaning to prevent, limit, or restrain. In medicine, this can refer to cellular processes, pathways or treatments to prevent (inhibit) harmful events such as infections. Many drugs have also been developed to inhibit or prevent disease such as ACE inhibitors used to treat hypertension.

Inhibition


Inhibition is the process of inhibiting, restraining, limiting or preventing. Inhibition of cellular processes or activities occurs naturally and an example of where this has failed is hereditary angioedema. Drugs may prevent naturally-occurring inhibition of cellular pathways, or the drugs themselves may cause inhibition of a process or pathway.

Inhibitor


Inhibitor is a substance that blocks or prevents a chemical reaction or process.

Inhibitors


Inhibitors: plural of inhibitor; substances that prevent or block chemical processes or reactions.

Injection site reaction


Injection site reaction is inflammation at the site of an injection into or through the skin. Most commonly it develops at the site of a recent injection, but rarely may occur at a previous injection site.

Injection-site reaction


Injection-site reaction is inflammation at the site of an injection into or through the skin. Most commonly it develops at the site of a recent injection, but rarely may occur at a previous injection site.

Innate


Innate is an adjective pertaining to being present from birth, inborn, is not acquired later in life.

Inoculate


Inoculate is a verb meaning to introduce microorganisms or cells into a culture medium or a living body, eg, the microbiologist will inoculate an agar plate to grow bacteria.

Inoculated


Inoculated is the past tense of the verb to inoculate, having introduced microorganisms or cells to grow in culture medium or a living body, eg, the doctor inoculated the patient to prevent smallpox.

Inoculation


Inoculation is the process of introducing microorganisms or cells to grow in culture medium or a living body. Inoculation is often used synonymously with immunisation (vaccination) using a live vaccine through abraded skin as was done for smallpox prophylaxis .

Insulin


Insulin is a pancreatic hormone which controls blood glucose (sugar) levels.

Insulins


Insulins: plural of insulin; natural pancreatic and synthetic hormones important in the control of blood glucose (sugar) level.

Integument


Integument is an enveloping layer, ie, the skin and mucosal surfaces of a human.

Intercellular


Intercellular is an adjective meaning between cells.

Interface


 An interface is a junction between two zones or structures.

Interface dermatitis


Interface dermatitis is a histological term describing inflammation at the junction (interface) between the epidermis and dermis. It may be lichenoid or vacuolar.

Intergluteal


Intergluteal is an adjective pertaining to the space between the gluteal muscles of the buttocks.

Interleukin


Interleukin means between leukocytes; a cytokine produced by a white blood cell (leukocyte) to act on another white blood cell (leukocyte). There are many different interleukins involved in both innate and adaptive immune responses.

Interleukins


Interleukins: plural of interleukin; cytokines produced by white blood cells to act on other white blood cells in both innate and adaptive immune responses.

Interphalangeal


Interphalangeal is an adjective meaning 'between the phalanges', the bones of fingers and toes..

Interstitial


Interstitial is an adjective pertaining to the interstitium, the intercellular connective tissue.

Interstitium


Interstitium is the intercellular connective tissue; tissue that holds the body layers together.

Intertriginous


Intertriginous is an adjective pertaining to intertrigo, between the folds, a body site where two areas of skin rub or touch, such as the armpit or groin.

Intertrigo


Intertrigo is a rash affecting body folds due to friction between adjacent skin sites.

Intra-articular


Intra-articular is an adjective meaning into or within a joint space.

Intraarticular


Intraarticular is an adjective meaning into or within a joint space.

Intracellular


Intracellular is an adjective pertaining to the inside of a cell, within a cell.

Intracorneal


Intracorneal is an adjective which, when used in dermatopathology, means within the horny, outer layer of the skin, ie, within the stratum corneum. It also means within the cornea of the eye.

Intracranial


Intracranial is an adjective to describe being inside or within the cranium (skull).

Intracytoplasmic


Intracytoplasmic is an adjective used to describe being in (within) the cytoplasm of a cell.

Intradermal


Intradermal is an adjective to describe being within the dermis.

Intradermal naevus


Intradermal naevus, also called a dermal naevus, (American spelling nevus) is a benign melanocytic naevus (mole) located entirely within the dermis.

Intraepidermal


Intraepidermal is an adjective to describe being within the epidermis.

Intralymphatic


Intralymphatic is an adjective meaning to be inside (within) a lymphatic vessel.

Intramuscular


Intramuscular: an adjective pertaining to within muscle; often used to describe an injection given into muscle.

Intrauterine


Intrauterine is an adjective referring to being within (inside) the uterus.

Intravaginal


Intravaginal is an adjective pertaining to being within or inside the vagina, the birth canal.

Intravascular


Intravascular is an adjective meaning to be inside (within) a blood vessel or lymphatic vessel.

Introitus


Introitus is from the Latin 'to go into', so is an entry point to a tube or hollow organ.

Intron


Intron is a sequence of DNA or RNA that is cut out of the RNA transcript before translation into a protein.

Invasive


Invasive is an adjective pertaining to invasion, the reaching into or taking over.

Involution


Involution, when used in medicine, means the process of shrinking or turning inward.

Ipsilateral


Ipsilateral is an adjective pertaining to being on the same side of the body.

Iris lesion


Iris lesion is a skin lesion composed of concentric red rings. It is also called a target lesion or may be described as having a bull's eye appearance.

Irritant


Irritant is an agent that causes non-allergic inflammation. On exposure to skin, an irritant causes dermatitis if used often enough or in high enough concentration. Examples of a skin irritant include friction, wool, soap and water.

Irritants


Irritants: plural of irritant; agents that cause non-allergic inflammation. On exposure to skin, irritants cause a dermatitis if used often enough or in high enough concentration. Examples of skin irritants include friction, wool, soap and water.

Ischaemia


Ischaemia is insufficient blood supply resulting in a lack of oxygen reaching a tissue.

Ischaemic


Ischaemic is an adjective pertaining to ichaemia, the effects of inadequate blood supply and hence oxygen in a tissue.

Isomorphic


Isomorphic is an adjective used to describe having the same (iso) form or shape (morph).

Isomorphic phenomenon


Isomorphic (eponymous name Koebner) phenomenon is the involvement at a site of skin trauma or injury by a pre-existing inflammatory skin condition.

Isotonic


Isotonic is an adjective pertaining to having the same comparative osmotic pressure.

Isotopic response


Isotopic response is the appearance of a new skin problem at the site of a previous unrelated skin condition.

J


Jaundice


Jaundice is the yellowing of the skin, mucous membranes, and sclerae due to elevated bile in the blood.

Junction naevus


A junction naevus (US English: nevus) is a congenital or acquired melanocytic naevus in which the naevus cells reside at the junction between the base of the epidermis and the dermis.

Junctional naevus


Junctional naevus (American spelling nevus) is a benign melanocytic naevus (mole) composed of melanocytes only along the dermoepidermal junction.

Juvenile


Juvenile can be a noun or adjective pertaining to a young person or child.

K


Karyotype


Karyotype is the number and appearance of chromosomes assessed during mitosis (cell division).

Keratin


Keratin is a family of proteins produced by keratinocytes, and forming the bulk of the epidermis, hair and nails.

Keratinisation


Keratinisation (American spelling keratinization) is the process by which skin cells mature and produce keratin proteins.

Keratinocyte


Keratinocyte is the skin cell that is the major building block of the epidermis. It produces keratin.

Keratinocyte cancer


Keratinocyte cancer is a generic term for a malignant neoplasm derived from keratinocytes, either from basal cell keratinocytes or squamous cell keratinocytes.

Keratinocytes


Keratinocytes: plural of keratinocyte; the skin cells that are the major building blocks of the epidermis. Keratinocytes produce keratin proteins.

Keratinocytic


Keratinocytic is an adjective pertaining to keratinocytes, the main skin cell in the epidermis.

Keratinocytic cancer


Keratinocytic cancer is a generic term for a malignant neoplasm derived from keratinocytes, either from basal cell keratinocytes or squamous cell keratinocytes.

Keratitis


Keratitis is inflammation of the cornea.

Keratoderma


Keratoderma is thickening of the skin, typically of the palms and soles. Keratoderma may be diffuse or localised.

Keratolytic


Keratolytic is an adjective and noun pertaining to the softening or destruction of keratin.

Keratolytics


Keratolytics: plural of keratolytic; topical agents that soften scaly or thickened skin.

Keratoses


Keratoses: plural of keratosis; any scaly skin lesions.

Keratosis


Keratosis is a descriptive word for any scaly skin lesion.

Keratotic


Keratotic is an adjective pertaining to keratin(s), proteins produced by keratinocytes to make hair, nail, and the outer protective barrier of the skin.

Ketoacidosis


Ketoacidosis is the accumulation of keto acids and acetone in the body, resulting in a characteristic smell in the breath and sweat. Ketoacidosis occurs in diabetes, starvation, and prolonged alcoholism.

Ketosis


Ketosis follows the metabolism of fat resulting in an excess of ketones such as acetone; it is typically found in under-treated diabetes and in people who follow a diet that is very low in carbohydrates.

Köbner


The Köbner phenomenon refers to the tendency of several skin conditions to affect areas subjected to injury.

Koebner


Koebner was a German dermatologist in the 19th century who first described the isomorphic response now often known eponymously as the Koebner phenomenon.

Koebner phenomenon


Koebner phenomenon, also known as the isomorphic phenomenon, is the flare of a pre-existing inflammatory skin condition involving a site of skin trauma or injury such as a scratch or burn.

Koebnerised


Koebnerised is an adjective pertaining to the Koebner phenomenon, a pre-existing inflammatory skin disease that has flared at a site of skin trauma.

Koilocyte


Koilocyte is a histological term for a 'hollow' vacuolated squamous cell infected with the human papillomavirus.

Koilocytes


Koilocytes: plural of koilocyte; hollow-looking squamous cells infected with human papillomavirus.

Koilonychia


Koilonychia is a concave or spoon-shaped nail.

L


Labia


Labia: plural of labium; lips.

Labial


Labial is an adjective pertaining to labia, lips.

Labium


Labium is a lip.

Lacrimal


Lacrimal is an adjective pertaining to tears.

Lactobacillary


Lactobacillary is an adjective referring to lactobacilli, Gram-positive rod-shaped bacteria that produce lactic acid.

Lactobacilli


Lactobacilli: plural of lactobacillus; members of a large genus of Gram-positive rod-shaped bacteria that produce lactic acid. There are currently over 50 species of lactobacilli known. Some lactobacilli species may be found in the microbiome of the mouth, vagina, and intestinal tract.

Lactobacillus


Lactobacillus is a large genus of Gram-positive rod-shaped bacteria that produce lactic acid. There are currently over 50 species of lactobacillus known. Some lactobacillus species can live in the microbiome of the mouth, the intestinal tract, and the vagina.

Lamella


Lamella is a thin layer.

Lamina


Lamina is a thin layer.

Lamina densa


Lamina densa is the middle layer of the basement membrane (zone) between the epidermis and dermis. It is found just below the lamina lucida and is mainly composed of type IV collagen.

Langerhans cell


Langerhans cell is a specialised dendritic cell that presents antigens to the immune system. The Langerhans cell is characterised on electron microscopy by cytoplasmic Birbeck granules.

Langerhans cells


Langerhans cells: plural of Langerhans cell; specialised dendritic cells that present antigens to the immune system. They derive from the monocyte-macrophage lineage. Langerhans cells are characterised by cytoplasmic Birbeck granules. They reside in the prickle cell layer of the epidermis and migrate to the lymph nodes.

Larva


Larva: an active immature form of some animals with a complex lifecycle.

Larvae


Larvae: plural of larva: an active immature form of some animals with a complex live cycle.

Larval


Larval: adjective pertaining to an active immature form of some animals with a complex life cycle.

Laryngeal


Laryngeal is an adjective pertaining to the larynx, that part of the throat between the tongue and trachea which includes the vocal cords.

Larynx


Larynx is the voice box; a structure in the throat situated above the trachea and below the tongue that contains the vocal cords and allows speech.

Laser


Laser is an acronym for light amplification of stimulated emission of radiation. Many uses have been found for laser devices including as a treatment in dermatology.

Lasers


Lasers: plural of laser; radiation-emitting devices with many uses including for dermatology treatments.

Latency


Latency is a period of concealment or dormancy. In medicine, it is the time between exposure to a disease-causing agent or process and the onset of symptoms or signs of disease. Latency is also the state of living or developing in a host without producing symptoms (dormancy).

Latent


Latent is an adjective pertaining to latency, being dormant or concealed.

Lateral


Lateral is an adjective relating to the side. In anatomy a lateral location means on or towards the side of a body part.

Latex agglutination test


Latex agglutination test uses latex beads covered with a specific antibody or antigen to identify elements in bodily fluid or tissue samples. A positive reaction is seen as a clumping (agglutination) of the latex beads.

Leiomyosarcoma


Leiomyosarcoma is a cancerous (malignant) growth of smooth muscle cells

Lentigines


Lentigines: plural of lentigo; pigmented flat or slightly raised skin lesions with a clearly defined edge.

Lentigo


Lentigo is a pigmented flat or slightly raised skin lesion with a clearly defined edge.

Lentigos


Lentigos: plural of lentigo; also called lentigines; pigmented flat or slightly raised skin lesions with a clearly defined edge.

Lesion


Lesion is any single area of altered tissue. A lesion may be solitary or one of many.

Lesional


Lesional is an adjective pertaining to a lesion, an area of altered tissue.

Lesions


Lesions: plural of lesion; areas of altered tissue.

Lethargy


Lethargy: lack of energy, feeling tired.

Leucocyte


Leucocyte (also spelt leukocyte) is another name for a white blood cell. Leucocytes may be granular (neutrophil, eosinophil, basophil) or non-granular (lymphocyte, monocyte).

Leucocytes


Leucocytes: plural of leucocyte; white blood cells.

Leucopenia


Leucopenia is a low or inadequate number of white cells in the blood.

Leukaemia


Leukaemia (American spelling leukemia) is a group of malignant blood cancers presenting as an abnormal increase in the number of a specific white blood cell type.

Leukaemias


Leukaemias: plural of leukaemia; (American spelling leukemias/leukemia); malignant disorders of white blood cells.

Leukocyte


Leukocyte (also spelt leucocyte) is another name for a white blood cell. Leukocytes are granular (neutrophil, eosinophil, basophil) or non-granular (lymphocyte,monocyte).

Leukocytes


Leukocytes: plural of leukocyte; white blood cells.

Leukocytoclasia


Leukocytoclasia is the infiltration and breakdown of neutrophils in inflammation.

Leukocytoclasis


Leukocytoclasis is the breakdown of infiltrating neutrophils in inflammation.

Leukocytoclastic


Leukocytoclastic is an adjective pertaining to leukocytoclasia; infiltration and breakdown of neutrophils in inflammation.

Leukocytosis


Leukocytosis is increased white blood cells circulating in the blood.

Leukoderma


Leukoderma means white skin, specifically white skin due to the loss of skin melanin. Also known as achromia and depigmented skin.

Leukonychia


Leukonychia is a completely or partially white nail.

Leukopenia


Leukopenia is a low or inadequate number of white cells in the blood.

Leukotriene


Leukotriene is a family of potent biological pro-inflammatory mediators. These mediators are produced in the body from arachidonic acid by the enzyme 5-lipoxygenase and are divided into groups according to their chemical structure.

Leukotrienes


Leukotrienes: plural of leukotriene; potent biological pro-inflammatory mediators. They are produced in the body from arachidonic acid by the enzyme 5-lipoxygenase and are divided into groups according to their chemical structure.

Lichenification


Lichenification is the process of skin thickening, becoming leathery with increased skin markings and scale due to chronic rubbing or scratching.

Lichenified


Lichenified is an adjective pertaining to lichenification, and describes thickened scaly skin with increased skin markings developing after chronic rubbing and scratching.

Lichenoid


Lichenoid is an adjective meaning to resemble lichen. Clinically lichenoid describes papules or plaques that look stuck-on to the skin like lichen on a rock or tree. In histology however lichenoid describes a band-like inflammation in the upper dermis.

Ligneous


Ligneous is an adjective to describe being woody. Ligneous conjunctivitis is a build up of fibrin causing thick woody growths on the conjunctiva.

Lindsay nails


Proximally white or pink-coloured nail with a distal darkening

Linear


Linear is an adjective to describe resembling a line, so is long and narrow.

Linear lesion


Linear lesion is a skin change forming a line. A linear lesion may be due to an external cause such as scratching, contact dermatitis, or the Koebner phenomenon activating a pre-existing dermatosis. However a linear lesion may also be developmental following a Blascko line, a dermatome, or a vascular or lymphatic vessel.

Linear lesions


Linear lesions: plural of linear lesion; lesions arranged in lines may be developmental, may be following linear structures such as vessels, or may be caused by extrinsic factors such as scratches or contact allergens typically plants.

Lipid


Lipid is a fat or fat-like substance insoluble in water.

Lipids


Lipids: plural of lipid; fats or fat-like substances insoluble in water. Examples include fatty acids or fatty acid derivatives, such as fats, waxes, or oils.

Lipocyte


Lipocyte is a fat cell, also called adipocyte, adipose cell.

Lipocytes


Lipocytes: plural of lipocyte; fat cells; also called adipocytes, adipose cells.

Lipoid


Lipoid is an adjective meaning fat-like or to resemble fat.

Lipolysis


Lipolysis is the breakdown of fat.

Lipophilic


Lipophilic is an adjective describing the ability to combine with or dissolve in lipids (fats).

Lipophobic


Lipophobic is an adjective describing the inability to combine with or dissolve in lipids (fats).

Livedo


Livedo is a mottled, typically bluish, vascular pattern in the skin due to slowed or obstructed vascular flow.

Livedoid


Livedoid is an adjective pertaining to livedo; a mottled, bluish, vascular pattern in the skin due to slowed or obstructed vascular flow.

Local anaesthetic


Local anaesthetic (American spelling anesthetic) is a drug that reduces pain and other sensations in a local area only. It is generally used by topical application or local infiltrative injection. Local anaesthetic can also be used as an adjective pertaining to the induction of local anaesthesia, eg, a local anaesthetic drug.

Localised


Localised is an adjective pertaining to local, a restricted area. A localised rash may involve just one body part such as the hands.

Longitudinal


Longitudinal is an adjective pertaining to longitude, meaning to run lengthwise (rather than crosswise) or east-west.

Lotion


Lotion is a liquid formulation for topical use. A lotion is usually a simple suspension or solution. After application of a lotion, the liquid phase evapourates leaving the active ingredient on the skin surface.

Lumbosacral


Lumbosacral is an adjective pertaining to the lumbar and sacral spine, lower back.

Lumen


Lumen is the inside of a tubular structure such as a blood vessel. A lumen is also the unit of measure for luminous flux from a light source.

Lumens


Lumens: plural of lumen; unit of luminous flux from a light source.

Lumina


Lumina: plural of lumen; inside of tubular structures such as blood vessels.

Lunula


Lunula is the moon- or crescent-shaped whitish area at the proximal base of a nail, and is the most distal visible part of the nail matrix.

Lunulae


Lunulae: plural of lunule; moon- or crescent-shaped whitish areas at the proximal base of the nails, representing the most distal visible part of the nail matrix.

Lunules


Lunules: plural of lunule; moon- or crescent-shaped whitish areas at the proximal base of the nails, representing the most distal visible part of the nail matrix.

Luteal


The phase in the menstrual cycle between ovulation and the beginning of the menstrual period.

Lymph


Lymph is a normal body fluid, typically colourless, formed from filtered blood in the capillary beds, carrying white blood cells through the lymph nodes, and returned to the circulation via lymphatic vessels into the thoracic duct.

Lymph node


Lymph node is a small encapsulated collection of immune cells that filters lymphatic fluid. A lymph node may enlarge in the presence of infection or cancer.

Lymph nodes


Lymph nodes: plural of lymph node; small encapsulated collections of immune cells that filter lymphatic fluid. Lymph nodes are found throughout the body, including the armpits and in the groin. Lymph nodes may enlarge in the presence of infection or cancer.

Lymphadenectomy


Lymphadenectomy is the surgical removal of lymph nodes.

Lymphadenitis


Lymphadenitis is inflammation of a lymph node.

Lymphadenopathic


Lymphadenopathic is an adjective pertaining to abnormal enlargement of lymph nodes.

Lymphadenopathy


Lymphadenopathy is the abnormal enlargement of lymph nodes.

Lymphangitis


Lymphangitis is inflammation of the lymphatic vessels and presents as red streaks from an infected area to the armpit or groin. 

Lymphatic


Lymphatic is an adjective and noun pertaining to lymph, its production, constituents, dissemination, or derivation.

Lymphatic vessel


Lymphatic vessel is a thin-walled tubular structure that conducts lymph from the peripheral tissues back to the blood circulation via the thoracic duct.

Lymphatic vessels


Lymphatic vessels: plural of lymphatic vessel; thin-walled tubular structures that conduct lymph from the peripheral tissues back to the blood circulation via the thoracic duct.

Lymphatics


Lymphatics: plural of lymphatic; by common usage lymphatics are the thin-walled tubular vessels that conduct lymph from the peripheral tissues back to the blood circulation via the thoracic duct.

Lymphocyte


Lymphocyte is a non-granular white blood cell that originates from stem cells in the bone marrow, is found in the blood, lymph tissue, and elsewhere in the body, and plays a major role in the immune system. The three main types of lymphocyte are B cells, T cells, and natural killer (NK) cells.

Lymphocytes


Lymphocytes: plural of lymphocyte; are non-granular white blood cells that originate in the bone marrow, are found in the blood, lymph tissue, and elsewhere in the body, and play major roles in the immune system.

Lymphocytic


Lymphocytic is an adjective pertaining to lymphocytes; white blood cells that originate in the bone marrow and play major roles in the immune reaction.

Lymphohistiocytic


Lymphohistiocytic is an adjective used in histology pertaining to both lymphocytes and histiocytes.

Lymphoid


Lymphoid is an adjective pertaining to lymphocytes, lymph nodes, or lymph.

Lymphoma


Lymphoma is a malignant disorder of the lymphoid tissue. There are many types of lymphoma including primary cutaneous lymphomas.

Lymphomas


Lymphomas: plural of lymphoma; malignant disorders of the lymphoid tissues.

Lymphomatoid


Lymphomatoid is an adjective used in histopathology to describe resembling lymphoma, a malignant disorder of lymphoid tissue.

Lymphopenia


Lymphopenia is a low or inadequate number of lymphocyte white cells in the blood.

Lymphoproliferative


Lymphoproliferative is an adjective pertaining to the production of lymphocytes.

Lysis


Lysis is a process of disintegration or dissolution. It may be used to describe the breakdown of adhesions, cells, or bacteria.

Lysosomal


Lysosomal is an adjective pertaining to lysosomes, membrane-bound cytoplasmic organelles in cells that contain hydrolytic enzymes.

Lysosome


Lysosome is a membrane-bound cytoplasmic organelle in a cell that contains hydrolytic enzymes.

Lysosomes


Lysosomes: plural of lysosome; membrane-bound cytoplasmic organelles in cells that contain hydrolytic enzymes.

Lysosomotropic


Lysosomotropic is an adjective describing the ability to penetrate lysosomes.

M


Macerate


Macerate is a verb meaning to soften.

Macerated


Macerated is a verb and adjective related to maceration, the process of softening. In dermatology, macerated describes moist peeling skin such as between the toes after inadequate drying.

Maceration


Maceration is the process of softening. In dermatology, maceration describes moist peeling skin such as between the toes after inadequate drying.

Macrocephaly


Macrocephaly is an abnormally large head.

Macrocytic


Macrocytic is an adjective pertaining to macrocytosis, large red blood cells.

Macrocytosis


Macrocytosis: the presence of larger than normal red blood cells in the blood.

Macrolunulae


Macrolunulae: plural of macrolunule; large lunulae (half-moons) in the nails.

Macrophage


Macrophage literally means big eater, and is another name for the histiocyte, a monocyte that has settled in the tissues including the skin. The macrophage is an actively migratory and phagocytic antigen-presenting cell, important in type IV hypersensitivity reactions and granuloma formation.

Macrophages


Macrophages: plural of macrophage; macrophages are actively migratory and phagocytic antigen-presenting cells in the tissues including skin.

Macrophagic


Macrophagic means relating to macrophages. Macrophages are large white blood cells and phagocytes — cells that ingests foreign material (‘macrophage’ literally means ‘big eater’). Macrophages destroy particles such as bacteria, viruses, fungi, and parasites. Macrophages are found in many tissues, including the skin. They are derived from monocytes, which are produced by stem cells in the bone marrow.

Macroscopic


Macroscopic is an adjective meaning large enough to be visible with the naked eye.

Macrovascular


Macrovascular is an adjective pertaining to large blood vessels such as arteries and veins.

Macular


Macular is an adjective pertaining to a macule(s), a spot(s) such as the macule of the eye or macules on the skin.

Macule


Macule is a flat spot. By definition a skin macule is less than 1 cm in diameter, and is altered in colour without being elevated.

Macules


Macules: plural of macule; small spots less than 1cm in diameter altered in colour but usually not elevated.

Maculopapular


Maculopapular is an adjective pertaining to both flat macules and bumpy papules.

Madarosis


Madarosis is the loss of either eyebrows, eyelashes, or both.

Magnetic resonance imaging


Magnetic resonance imaging (acronym MRI) is a medical imaging technique using a magnetic field, radiowaves and a computer to produce detailed images. MRI is useful for soft tissue injuries affecting muscles, tendons or ligaments, for assessing the brain and spinal cord, and for finding tumours. MRI does not use x-rays.

Magnetic-resonance imaging


Magnetic-resonance imaging (acronym MRI) is a medical imaging technique using a magnetic field, radiowaves and a computer to produce detailed images. MRI is useful for soft tissue injuries affecting muscles, tendons or ligaments, for assessing the brain and spinal cord, and for finding tumours. MRI does not use x-rays.

Malaise


Malaise is a general feeling of unwellness or sickness.

Malar


Malar is an adjective pertaining to the malar bone of the cheek.

Malformation


Malformation is a congenital abnormality due to faulty development of a body part.

Malformations


Malformations: plural of malformation; congenital abnormalities due to faulty development of a body part(s).

Malignancy


Malignancy is cancer, the presence of potentially invasive malignant cells.

Malignant


Malignant is an adjective used to describe having a poor prognosis if left untreated. Malignant is most commonly used for cancer such as a malignant melanoma.

Malodorous


Malodorous is an adjective pertaining to malodour, an unpleasant or bad smell.

Malodour


Malodour is a bad or unpleasant smell.

Mammography


Mammography: is imaging of the breast using low-energy X-rays.

Mandible


Mandible is the lower jaw or jawbone.

Manifest


Manifest is used as a verb in medicine meaning to express or appear, eg, COVID-19 may first manifest as a fever.

Manifestation


Manifestation, when used in medicine, is a symptom or sign of a disease or condition.

Manifestations


Manifestations: plural of manifestation; symptoms or signs of disease.

MAPK


MAPK is the acronym for mitogen-activated protein kinase. The MAPK signalling pathway mediates cell growth and survival.

Marginal


Marginal is an adjective pertaining to the margin, being on the edge. In dermatology, the word 'marginal' may be used for being on the edge of a lesion or edge of a body part.

Mast cell


Mast cell is a granulocytic white blood cell found in the connective tissue. Mast cell granules release histamine and other mediators. The mast cell is paticularly important in the immune response to parasitic infections, and is also activated in some allergic reactions.

Mast cells


Mast cells: plural of mast cell; granulocytic white blood cells found in the connective tissue. Mast cell granules release histamine and other mediators. Mast cells are particularly important in the immune response to parasitic infections, and are also activated in some allergic reactions.

Matrix metalloproteinase


Matrix metalloproteinase (acronym MMP) is a family of enzymes within the superfamily of matrixins involved in extracellular matrix regulation, inflammation, scarring and wound repair. The matrix metalloproteinase family can be divided into two major groups - those that breakdown collagen and those affecting other molecules.

Matrix metalloproteinases


Matrix metalloproteinases: plural of matrix metalloproteinase; enzymes involved in extracellular matrix regulation, inflammation, scarring and wound repair.

Matrix of nail


Matrix of nail is the tissue from which the nail is formed. The dorsal (outer) nail plate is formed from the proximal nail matrix under the nail fold but the ventral (inner) nail plate is formed from the nail bed.

Maximal


Maximal is an adjective pertaining to maximum, the biggest, highest, largest possible.

Mean


Mean is a noun used in statistics for the average. It is derived by adding up all the numbers and dividing by the number of items.

Mean corpuscular volume


Mean corpuscular volume (acronym MCV) is a measure of the size of peripheral red blood cells. The normal range is between 65 fL and 100 fL.

Medial


Medial is an adjective pertaining to the median, the midline or middle.

Median


Median is a noun and adjective. As an adjective, median pertains to the middle. In anatomy, the median axis of the body is the midline, the median nerve is in the middle of the wrist. Median is used as a noun in statistics for the middle value in a range, dividing the probability in half.

Median canaliform dystrophy


Median canaliform dystrophy results in a longitudinal groove in a nail plate.

Mediator


Mediator is a go-between. In medicine, a mediator is a chemical that transmits a signal or information.

Mediators


Mediators: plural of mediator; in medicine mediators are chemicals that transmit signals or information.

MEK


MEK is the acronym for mitogen-activated, extracellular signal-regulated kinase, an enzyme in the MAPK signalling pathway which mediates cell growth and survival.

MEK inhibitor


MEK inhibitor is a drug that directly targets a mutated MEK protein to shrink or slow the growth of a cancer.

MEK inhibitors


MEK inhibitors: plural of MEK inhbitor; drugs that directly target a mutated MEK protein to shrink or slow the growth of a cancer.

Melaena


Melaena: is black stools due to altered blood in the faeces.

Melanin


Melanin is a family of biological pigments derived from the amino acid tyrosine, and produced by melanocytes.

Melanins


Melanins: plural of melanin; biological pigments derived from the amino acid tyrosine, and produced by melanocytes.

Melanocyte


Melanocyte is a dendritic cell found in the basal layer of the epidermis, and other sites. The epidermal melanocyte produces melanin to protect the skin from damage due to ultraviolet radiation.

Melanocyte stimulating hormone


Melanocyte stimulating hormone (acronym MSH) is one of the protein products of the pro-opiomelanocortin gene. There are three forms of MSH: -alpha, -beta and -gamma, with alpha being the most active in humans. MSH-alpha has many effects including on the pigmentary and inflammatory systems as well as on body weight.

Melanocyte-stimulating hormone


Melanocyte-stimulating hormone (acronym MSH) is one of the protein products of the pro-opiomelanocortin gene. There are three forms of MSH: -alpha, -beta and -gamma, with alpha being the most active in humans. MSH-alpha has many effects including on the pigmentary and inflammatory systems as well as on body weight.

Melanocytes


Melanocytes: plural of melanocyte; dendritic pigment-forming cells found in the basal layer of the epidermis, and other sites. Epidermal melanocytes produce melanin to protect the skin from damage due to ultraviolet radiation.

Melanocytic


Melanocytic is an adjective pertaining to melanocytes, the pigment-producing cells in the skin.

Melanoderma


Melanoderma is patchy or diffuse darkening of the skin due to increased melanin.

Melanodermas


Melanodermas: plural of melanoderma; conditions presenting as patchy or diffuse darkening of the skin due to increased melanin.

Melanogenesis


Melanogenesis is the production of melanin in melanocytes.

Melanoma


Melanoma is a cancerous (malignant) growth of melanocytes (pigment cells).

Melanomas


Melanomas: plural of melanoma; cancerous (malignant) growths of melanocytes (pigment cells).

Melanonychia


Melanonychia is a band of brown-black discolouration due to melanin in a nail plate. Melanonychia may be transverse or longitudinal, single or multiple, due to melanocyte activation or tumours either benign or malignant.

Melanophage


Melanophage is a histiocyte (macrophage) which has ingested melanin granules or fragments.

Melanophages


Melanophages: plural of melanophage; histiocytes (macrophages) which have ingested melanin granules or fragments.

Melanosome


Melanosome is a cytoplasmic organelle involved in the synthesis, storage and transport of melanin, and found in melanocytes.

Melanosomes


Melanosomes: plural of melanosome; cytoplasmic organelles involved in the synthesis, storage and transport of melanin, found in melanocytes.

Menarche


Menarche is the onset of menstruation in puberty.

Meningitis


Meningitis is inflammation of the meninges, the membrane covering of the brain and the spinal cord.

Meralgia


Meralgia means thigh pain, from the Greek 'mero' (thigh) and 'algia' (pain). In medicine, meralgia is used to describe pain, tingling or numbness of the thigh due to a neurological cause.

Merkel cell


Merkel cell is a neuroendocrine cell found in the epidermis. The exact function of the Merkel cell is not known but is thought to be involved in mechanoreception as it is associated with a nerve ending especially in highly tactile sites such as fingertips and lips.

Merkel cells


Merkel cells: plural of Merkel cell; neuroendocrine cells found in the epidermis. Their exact function is uncertain but they are thought to be involved in mechanoreception as they are associated with nerve endings especially in highly tactile sites such as lips and fingertips.

Mesothelioma


Mesothelioma is a malignant tumour arising from the mesothelial lining of the pleura, peritoneum, pericardium and tunica vaginalis. Pleural mesothelioma is the most common of these and is almost always due to asbestos exposure.

Messenger RNA


Messenger RNA (acronym mRNA) is the molecule responsible for carrying genetic information from the DNA (following transcription) to the protein-synthesising ribosomes for translation.

Metabolism


Metabolism is a cellular process in which complex molecules derived from foodstuffs, are broken down to produce energy for the cell.

Metabolite


Metabolite is a substance produced as a result of metabolism, such as food converted to the metabolite glucose.

Metabolites


Metabolites: plural of metabolite; substances produced as a result of metabolism, such as food converted to the metabolites glucose and urea.

Metacarpal


Metacarpal is an adjective and noun pertaining to the metacarpus, bones in the hand located between the carpal and phalangeal bones.

Metacarpals


Metacarpals: plural of metacarpal; the five bones in each hand making up the metacarpus located between the carpal and phalangeal bones.

Metaplasia


Metaplasia is the transformation of one type of cell into another because of a changed environment.

Metastases


Metastases: plural of metastasis; multiple secondary deposits of a disease in other parts of the body, away from the site of origin. It is most commonly used to refer to cancer deposits but can also mean deposits of infection or other cells.

Metastasis


Metastasis is a secondary deposit of bacteria or cells, including cancer cells, away from the site of origin.

Metastasise


Metastasise (American spelling metastasize) is a verb meaning to spread or transfer. In medicine, it is used to mean the spread of cells or infections within the body away from the original site of involvement.

Metastatic


Metastatic is an adjective pertaining to a metastasis, a secondary deposit of bacteria or cells away from the original site of involvement.

Micro-organism


Micro-organism, also called a microbe, is any living organism that is not visible with the naked eye, eg, a bacterium, virus, protozoan, yeast.

Micro-organisms


Micro-organisms: plural of micro-organism; also called microbes; any living organisms that are not visible with the naked eye, eg, bacteria, viruses, protozoa, yeasts.

Microabscess


Microabscess is a tiny collection of neutrophils, eosinophils, or atypical cells.

Microabscesses


Microabscesses: plural of microabscess; tiny collections of neutrophils, eosinophils, or atypical cells.

Microarray


Microarray is a laboratory tool used in the analysis of thousands of tiny samples of DNA, RNA or proteins.

Microarrays


Microarrays: plural of microarray; laboratory tools used in the analysis of thousands of tiny samples of DNA, RNA, or proteins.

Microbe


Microbe, also called a micro-organism, is a generic word for any living organism that is not visible with the naked eye, eg, bacterium, virus, protozoan, yeast.

Microbes


Microbes: plural of microbe; a generic word for any living organisms not visible to the naked eye, eg, bacteria, viruses, protozoa, yeasts.

Microbiome


Microbiome, also called microbiota, is the collection of microorganisms that normally inhabit an organ or site, eg, the skin microbiome.

Microcephaly


Microcephaly is an abnormally small head.

Microcytic


Microcytic is an adjective pertaining to microcytosis, small red blood cells.

Microcytosis


Microcytosis literally means small cells, but is specifically used to mean smaller than normal red blood cells in the peripheral blood. Microcytosis is defined as a mean corpuscular volume (MCV) less than 65 femtolitres (fL).

Microorganism


Microorganism, also called a microbe, is any living organism that is not visible with the naked eye, eg, a bacterium, virus, protozoan, yeast.

Microorganisms


Microorganisms: plural of microorganism; any living organisms that are not visible with the naked eye, eg, bacteria, viruses, protozoa, yeasts.

Microscope


Microscope is an instrument for magnifying a sample such as a skin biopsy. Examples include the light microscope and the electron microscope.

Microscopes


Microscopes: plural of microscope; tools used to magnify samples, examples include light and electron microscopes.

Microscopic


Microscopic is an adjective pertaining to a microscope, an instrument for magnification. Microscopic may be used to describe small objects, cells, organisms, or details requiring a microscope to be seen.

Microscopy


Microscopy is the practice of using microscopes to view objects or details that cannot be seen by the naked eye. Light microscopy and electron microscopy are examples.

Microvascular


Microvascular is an adjective pertaining to the smallest blood vessels, usually capillaries.

Midline


Midline is an imaginary line through the middle of a structure such that the two sides are equal.

Milia


Milia: plural of milium; small white papules formed by keratin trapped in the superficial layers of the skin.

Miliary


Miliary is an adjective pertaining to millet seeds, used to describe multiple tiny lesions.

Milium


Milium is a small white papule formed by keratin trapped in the superficial layers of the skin.

Mite


Mite is a minute, small arachnid, eg, scabies mite.

Mites


Mite: plural of mite; minute, small arachnids, eg, scabies mites.

Mitoses


Mitoses: plural of mitosis; normal process of cell division visible on histology of tissues.

Mitosis


Mitosis is the normal process of cell division to produce two identical cells.

Mitotic


Mitotic is an adjective pertaining to mitosis, the normal process of cell division.

Mitotic index


Mitotic index is a count of the number of mitotic figures visible on microscopy of a tissue section, giving an estimate of how fast the cells are dividing.

Molecular


Molecular is an adjective pertaining to a molecule(s), an entity composed of two or more atoms.

Molecule


Molecule is an entity composed of two or more atoms.

Molecules


Molecules: plural of molecule; entities composed of two or more atoms.

Monoarthritis


Monoarthritis is inflammation of a single joint.

Monoclonal


Monoclonal is an adjective pertaining to a single clone, a group of identical units derived from an original single cell. Monoclonal cells form from a single cell. Monoclonal antibodies are produced by a single clone of plasma cells and have identical antigen-recognising sequences.

Monocular


Monocular is an adjective pertaining to one eye.

Monocyte


Monocyte is a mononuclear white blood cell made in the bone marrow and found only in the bloodstream. A monocyte becomes a macrophage as it actively migrates through body tissues.

Monocytes


Monocytes: plural of monocyte; circulating immune cells that become macrophages after migrating into body tissues.

Monocytic


Monocytic is an adjective pertaining to cells derived from the monocyte-macrophage lineage.

Monogenic


Monogenic is an adjective pertaining to a single gene.

Monomorphic


Monomorphic is an adjective pertaining to one shape or form, all components having the same or an essentially similar appearance. A monomorphic rash looks the same all over, compared to being dimorphic or polymorphic.

Monomorphous


Monomorphous (British spelling monomorphic) is an adjective pertaining to one shape or form, all components having the same or essentially similar appearance.

Morbidity


Morbidity is the state of being unwell.

Morbilliform


Morbilliform is an adjective pertaining to the eruption of measles, measles-like rashes. Typically a morbilliform rash is generalised and erythematous, with macules or papules.

Morphological


Morphological is an adjective pertaining to morphology, the form and structure of things.

Morphologically


Morphologically is an adjective pertaining to morphology, the form or structure of things.

Morphologies


Morphologies: plural of morphology; forms or structures of things.

Morphology


Morphology is the structure and form of things, and also the study of the forms of things. In dermatology the description of an individual skin lesion is the lesion morphology.

Mortality


Mortality is the state of dying or death.

Motile


Motile is an adjective pertaining to motility, the ability of an organism to move of its own accord.

Motility


Motility is the ability of an organism to self-propel or move spontaneously under its own power.

MRI


MRI is the acronym for magnetic resonance imaging; a medical imaging technique using a magnetic field, radiowaves and a computer to produce detailed images. MRI is useful for soft tissue injuries affecting muscles, tendons or ligaments, for assessing the brain and spinal cord, and for looking for tumours. MRI does not use x-rays.

mRNA


mRNA is the acronym for messenger RNA, the molecule responsible for carrying genetic information from the DNA (after transcription) to the protein-synthesising ribosomes for translation.

MSH


MSH is the acronym for melanocyte stimulating hormone, one of the protein products of the pro-opiomelanocortin gene. There are three forms of MSH: -alpha, -beta and -gamma, with alpha being the most active in humans. MSH-alpha has many effects including on the pigmentary and inflammatory systems as well as on body weight.

Mucin


Mucin is a normal component of the ground substance surrounding the cells and fibres of the dermis. Mucin is mainly composed of hyaluronic , and has a stringy clear appearance.

Mucinosis


Mucinosis is a disorder characterised by the deposition of excessive mucin in the dermis.

Mucocutaneous


Mucocutaneous is an adjective pertaining to the skin and mucous membranes.

Mucosa


Mucosa, also called mucous membrane, is the moist lining of body cavities and passages that can be exposed to the external envirnoment, eg, the mucosa of the mouth, nose, eyes, and anogenital area.

Mucosae


Mucosae: plural of mucosa; the moist linings of body cavities and passages that are exposed to the external envirnoment.

Mucosal


Mucosal is an adjective pertaining to mucosa(e), the moist mucous membranes that line all body cavities and passages that are exposed to the external environment.

Mucositis


Mucositis is inflammation of the mucosa(e) (mucous membranes).

Mucous


Mucous is an adjective pertaining to mucus, the secretion from mucous membranes.

Mucous membrane


Mucous membrane, also called mucosa, is the moist lining of internal body cavities and passages that open onto the skin surface, eg, the mucous membrane of the mouth, nose, eyes, and anogenital area.

Mucous membranes


Mucous membranes: plural of mucous membrane; the moist linings of internal body passages and cavities that open onto the skin surface, eg, the mucous membranes of the mouth, nose, eyes, and anogenital area.

Mucus


Mucus is the secretion from mucous membranes, the moist linings of internal body passages and cavities that open onto the skin surface.

Muehrcke lines


A pair of observable, non-palpable, horizontal (transverse) white lines across the nail due to variable blood flow

Multibacillary


Multibacillary is an adjective meaning many bacteria.

Multicentric


Multicentric is an adjective meaning many centres. It is used in medicine to describe a disease process affecting more than one site.

Multidisciplinary


Multidisciplinary is an adjective pertaining to multiple disciplines; a multidisciplinary team would involve academics or specialists from more than one area of expertise.

Multifactorial


Multifactorial is an adjective to describe having more than one factor involved, eg, multifactorial hand dermatitis due to atopic dermatitis (genetic factors) and contact dermatitis (environmental factors).

Multigravida


Multigravida describes a woman who has been pregnant more than once.

Multinucleate


Multinucleate is an adjective used in histology to describe having two or more nuclei, eg, a multinucleate giant cell.

Multinucleated


Multinucleated is an adjective used in histology to describe having two or more nuclei.

Multinucleation


Multinucleation is the process of forming multinucleate cells, cells with two or more nuclei.

Multiparous


Multiparous means having given birth on more than one baby.

Multiple sclerosis


Multiple sclerosis: a condition of the brain and spine that affects movement, sensation, and body function.

Multisystem


Multisystem is an adjective pertaining to many systems. In medicine it is used to describe a disease process affecting more than one organ or tissue.

Muscle contraction


A muscle contraction is the process of a muscle developing tension; it is the opposite of relaxation.

Muscle contractions


Muscle contractions occur as a muscle develops tension; it is the opposite of relaxation.

Musculoskeletal


Musculoskeletal is an adjective referring to muscles, tendons, bones, joints, and associated tissues.

Mutagen


Mutagen is a physical or chemical agent that alters or changes genetic material; a mutagen causes a mutation in the DNA or RNA sequence.

Mutagens


Mutagen: plural of mutagen; physical or chemical agents that alter or change genetic material.

Mutant


Mutant is an organism expressing a genetic mutation, a change in the genetic message.

Mutants


Mutants: plural of mutant; organisms that express genetic mutations, changes in the genetic messages.

Mutate


Mutate is a verb meaning to change. In medicine, mutate is typically used to mean changing of the genetic material.

Mutation


Mutation is a permanent transmissible change in the genetic material, ie, a gene mutation, which may or may not have any visible effect on the phenotype. Common usage tends to mean a visible effect as in a disease-causing mutation.

Mutations


Mutations: plural of mutation; permanent transmissible changes in the genetic material.

Myalgia


Myalgia is muscle pain.

Mycelium


Mycelium is the vegetative part of a fungus that collects nutrients.

Mycosis


Mycosis is a fungal infection.

Myeloid


Myeloid is an adjective pertaining to the bone marrow.

Myocarditis


Myocarditis is inflammation of the heart muscle.

Myopathy


Myopathy is any muscle disease.

Myositis


Myositis is inflammation of a muscle(s).

Myxoid


Myxoid is an adjective meaning mucus-like, but rarely pertains to mucus itself, eg, digital myxoid cyst, myxoid degeneration.

Myxoma


Myxoma, also called an angiomyxoma, is an acquired benign neoplasm composed of a mucinous matrix and prominent dilated capillaries. A myxoma may be solitary or one of many.

Myxomas


Myxomas: plural of myxoma; also called angiomyxomas; acquired benign neoplasms composed of mucinous matrix and prominent dilated capillaries. Multiple myxomas can be a marker of Carbey complex.

Myxomatous


Myxomatous is an adjective used in histopathology to describe the appearance or presence of extra ground substance in a tissue.

N


Naevi


Naevi: plural of naevus (American spelling nevi/nevus); benign growths of a normal skin component, either congenital or acquired. Common usage tends to mean melanocytic naevi (moles).

Naevoid


Naevoid: adjective pertaining to or resembling a naevus. 

Naevus


Naevus (American spelling nevus) is a benign congenital hamartoma or acquired growth of a normal skin component. It is commonly used to refer to a melanocytic naevus (mole), but is really any skin hamartoma.

Nail


Nail is an epidermal adnexal structure found on the end of a finger or toe. The nail plate is composed of horny cells containing keratin produced by the nail matrix and nail bed.

Nail fold


Nail fold is the fold of skin at the proximal end (base) of the nailplate under which the nail matrix is located.

Nail matrix


Nail matrix consists of specialised cells that produce the nail plate. It is located at the end of the digit (finger or toe) under the the skin beyond the distal phalangeal joint. It can be seen protruding as a white half-moon shape at the base of some nails

Nail plate


Nail plate is a hard, translucent structure made of keratin. It is not usually pigmented.

Nailfold


Nailfold is the fold of skin at the proximal end (base) of the nailplate under which the nail matrix is located.

Nails


Nails: plural of nail; are found on the distal ends of fingers and toes. The nail plates are composed of horny cells containing keratin produced by the nail matrix and nail bed. Healthy fingernails grow 0.1 mm per day and toenails grow 0.03 mm per day, but this varies with anatomical site, age, other physiological states, and disease.

Nares


Nare: plural of naris; the nostrils or nasal passages.

Naris


Naris is a nostril or nasal passage.

Nasopharyngeal


Nasopharyngeal is an adjective referring to the part of the throat located above the soft palate and behind the nose.

Nasopharyngitis


Nasopharyngitis is inflammation of the nasal passages and throat.

Nasopharynx


Nasopharynx is the part of the throat located above the soft palate and behind the nose.

Natural killer (NK) cell


Natural killer (NK) cell is a cytotoxic T lymphocyte involved in the innate immune system, able to induce programmed cell death (apoptosis) of cancer cells and cells infected with a virus.

Natural killer (NK) cells


Natural killer (NK) cells: plural of natural killer (NK) cell; cytotoxic T lymphocytes involved in the innate immune response. NK cells induce programmed cell death (apoptosis) in cancer cells or cells infected with a virus.

Natural killer cell


Natural killer cell (acronym NK cell) is a cytotoxic T lymphocyte involved in the innate immune system. The NK cell can induce programmed cell death (apoptosis) in cancer cells or cells infected with a virus.

Natural killer cells


Natural killer cells (acronym NK cells): plural of natural killer cell (NK cell); cytotoxic T lymphocytes involved in the innate immune system, able to induce programmed cell death (apoptosis).

Necrobiosis


Necrobiosis is a histological term for homogenisation of the dermis, typically associated with granuloma formation.

Necrosis


Necrosis is the death of cells or tissues.

Necrotic


Necrotic is an adjective pertaining to necrosis, cell or tissue death.

Necrotising


Necrotising (American spelling necrotizing) is an adjective pertaining to the process of necrosis, cell or tissue death; causing, associated with, or undergoing the process of necrosis.

Neoadjuvant


Neoadjuvant is an adjective pertaining to a helper given before the main treatment. Neoadjuvant chemotherapy may be recommended before surgery of a cancer to help shrink the tumour and kill any cancer cells that may have already spread. The aim is to make the surgery easier and more successful.

Neonatal


Neonatal is an adjective pertaining to newborns in the first 4 weeks after birth.

Neonate


Neonate is a newborn child; defined as an infant less than four weeks old.

Neonates


Neonates: plural of neonate; newborn children; defined as infants less than four weeks old.

Neoplasia


Neoplasia is the formation of a new growth which can be benign or malignant.

Neoplasm


Neoplasm is an abnormal proliferation of cells; it can be benign (harmless) or malignant (cancer).

Neoplasms


Neoplasms: plural of neoplasm; abnormal new growths of cells; they can be benign (harmless) or malignant (cancer).

Neoplastic


Neoplastic is an adjective pertaining to neoplasia, the formation of a new growth.

Nephritis


Nephritis is inflammation of the kidney.

Nephrotoxic


Nephrotoxic is an adjective pertaining to the ability of a chemical (eg, drug, poison, toxin) to damage the kidneys.

Nephrotoxicity


Nephrotoxicity is a measure of the ability of a chemical (eg, drug, poison, toxin) to damage the kidneys.

Nephrotoxin


Nephrotoxin is a chemical (eg, drug, poison, toxin) that can damage the kidneys.

Nerve


Nerve is a cellular fibre that transmits messages via an electrical current. A nerve may belong to the sensory, autonomic, or motor nervous system.

Nerve cell


Nerve cell, also called a neuron(e), consists of a cell body and a long dentrite(s) called an axon(s) along which electrical impulses pass to convey messages to other cells.

Nerve cells


Nerve cells: plural of nerve cell; also called neuron(e)s; consist of cell bodies and long dendrites (axons) along which electrical impulses pass to convey messages to other cells.

Nerves


Nerves: plural of nerve; cellular fibres (axons) that transmit sensory, autonomic or motor impulses through the body.

Neural


Neural is an adjective pertaining to a nerve.

Neuralgia


Neuralgia is a severe attack or spasm of pain that radiates along the course of one or more nerves.

Neurocutaneous


Neurocutaneous is an adjective describing a relationship or link between skin and nerves. It is typically used to describe cutaneous tumours derived either from ectopic neural tissue or peripheral nerves.

Neuroendocrine


Neuroendocrine is an adjective describing a link between the neural and endocrine systems.

Neurofibroma


Neurofibroma is a common benign tumour formed by the abnormal proliferation of a mixture of neuromesenchymal cells associated with a peripheral nerve.

Neurofibromas


Neurofibromas: plural of neurofibroma; common benign tumours formed by the abnormal proliferation of a mixture of neuromesenchymal cells associated with a peripheral nerve.

Neurofibromatosis


Neurofibromatosis (acronym NF) is a family of conditions characterised by the development of neurofibromas or schwannomas in the central nervous system, skin or both. Forms of neurofibromatosis include neurofibromatosis types 1, 2, 3, 4, and segmental neurofibromatosis (type 5).

Neurogenic


Neurogenic is an adjective to describe a neurological cause for symptoms or signs.

Neurologic


Neurologic is an adjective pertaining to neurology, the study of diseases of the nervous system, or the nervous system.

Neurological


Neurological is an adjective pertaining to the nervous system, or to neurology, the branch of medicine concerned with the structure, function, and diseases of the nervous system.

Neurologist


Neurologist is a medical specialist in the study, investigation, and treatment of diseases of the nervous system.

Neurology


Neurology is the study of the nervous system, its structure, function, and diseases.

Neuron


Neuron, also spelled neurone, is a dendritic nerve cell involved in the conduction of electrical impulses to carry messages to other cells.

Neurone


Neurone, also spelled neuron, is a dendritic nerve cell involved in the conduction of electrical impulses to carry messages to other cells.

Neurones


Neurones: plural of neurone; nerve cells.

Neurons


Neurons: plural of neuron; nerve cells.

Neuropathic


Neuropathic is an adjective pertaining to a neuropathy, any disease of, or damage to, the nervous system. It is typically used for diseases or damage to the peripheral nervous system, but may also relate to the central nervous system (brain and spinal cord).

Neuropathy


Neuropathy is any disease, damage, or dysfunction, of the nervous system or nerves.

Neurotoxic


Neurotoxic is an adjective pertaining to the damaging effects of a chemical (eg, drug, poison, toxin) on the brain and nervous tissue.

Neurotoxicity


Neurotoxicity is a measure of the ability of a chemical (eg, drug, poison, toxin) to damage the brain and other nerve tissue.

Neurotoxin


Neurotoxin is a chemical (eg, drug, poison, toxin) that can damage the brain and other nerve tissues.

Neurotransmitter


A neurotransmitter is a chemical released at a nerve ending when a nerve impulse arrives. The chemical transfers the impulse across a gap to another nerve or muscle fibre.

Neurotransmitters


Neurotransmitters are chemicals released at a nerve ending when a nerve impulse arrives. The chemical transfers the impulse across a gap to another nerve or muscle fibre.

Neurotropism


Neurotropism is the tendency of a virus or tumour to invade nerves or neural tissue.

Neutropenia


Neutropenia is a low or inadequate number of neutrophil white cells in the blood.

Neutrophil


Neutrophil, also known as a neutrophil leukocyte, polymorph, or neutrophilic polymorphonuclear leukocyte, is the most numerous type of granulocytic white blood cell (leukocyte). It is the first-line of defence in tissue damage and infection.

Neutrophilic


Neutrophilic is an adjective describing something that binds neutral dyes. More specifically in medicine, it is used to describe something associated with neutrophil leukocytes as in a neutrophilic infiltrate meaning inflammation involving neutrophils.

Neutrophils


Neutrophils are white blood cells (leukocytes) characterised by their role in mediating immune responses against infectious microorganisms. Neutrophils, along with eosinophils and basophils, are part of a group of white blood cells known as granulocytes.

Nevus


Nevus: a benign congenital hamartoma or acquired growth of a normal skin component. It is commonly used to refer to a melanocytic nevus (mole), but is really any skin hamartoma.

Nikolsky sign


Nikolsky sign is positive when slight rubbing of the skin results in exfoliation or shearing of the skin's outermost layer.

NK cell


NK cell is the acronym for a natural killer cell, a cytotoxic T-lymphocyte involved in the innate immune system to induce programmed cell death (apoptosis).

NK cells


NK cells, the acronym for natural killer cells, cytotoxic T-lymphocytes involved in the innate immune response to induce programmed cell death (apoptosis).

Nocebo


Nocebo is a detrimental or negative effect due to the belief an intervention will cause harm (the opposite of the placebo effect).

Nodal


Nodal is an adjective describing a knob. In medicine, nodal may be used to refer to rheumatic nodes, neural nodes, and lymph nodes.

Nodular


Nodular is an adjective pertaining to a nodule(s), a palpable skin bump greater than 1 cm in diameter.

Nodule


Nodule is an elevated, solid, palpable lesion more than 1 cm in diameter, usually located primarily in the dermis or subcutis. The greatest portion of the lesion may be above or beneath the skin surface.

Nodules


Nodules: plural of nodule; elevated, solid, palpable lesions > 1 cm in diameter.

Non-cicatrial


Non-cicatricial means non-scarring.

Non-cicatricial


Non-cicatricial is an adjective pertaining to not scarring.

Non-pitting oedema


Non-pitting oedema (American spelling edema) is tissue swelling which cannot be indented with pressure. It is typically due to lymphoedema.

Non-steroidal anti-inflammatory drug


Non-steroidal anti-inflammatory drug (acronym NSAID) is a class of medications used to treat inflammation, pain and fever.

Non-steroidal anti-inflammatory drugs


Non-steroidal anti-inflammatory drugs (acronym NSAIDs): plural of non-steroidal anti-inflammatory drug; medications used to treat inflammation, pain and fever.

Noncicatricial


Noncicatricial is an adjective pertaining to not scarring.

Nonsteroidal anti-inflammatory drug


Nonsteroidal anti-inflammatory drug (acronym NSAID) is a class of medications used to treat inflammation, fever and pain

Nonsteroidal anti-inflammatory drugs


Nonsteroidal anti-inflammatory drugs (acronym NSAIDs): plural of nonsteroidal anti-inflammatory drug; medications used to treat inflammation, pain and fever.

Nosocomial


Nosocomial is an adjective pertaining to a hospital, eg, a nosocomial infection is an infection acquired in hospital.

Notalgia


Notalgia means pain in the back, from the Greek 'nota' (back) and 'algia' (pain). In medicine, notalgia is used to describe pain, tingling or numbness of the back due to a neurological cause.

NSAID


NSAID is an acronym for nonsteroidal anti-inflammatory drug, non-steroidal anti-inflammatory drug.

NSAIDs


NSAIDs: plural of NSAID; acronym for nonsteroidal anti-inflammatory drugs, non-steroidal anti-inflammatory drugs.

Nuclear


Nuclear is an adjective pertaining to the nucleus, the centre or core. This may be the nucleus of an atom or the nucleus of a cell which contains its genetic material. A nuclear family is the core of parents and children, excluding grandparents, cousins, etc.

Nuclei


Nuclei: plural of nucleus; has many meanings including cores and centres as in nuclei of atoms, nuclei of cells, nuclei of neurones.

Nucleic acid


Nucleic acid is a long chain of nucleotides. There are two types of nucleic acid: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

Nucleic acids


Nucleic acids: plural of nucleic acid; chains of nucleotides resulting in either DNA or RNA.

Nucleotide


Nucleotide is the building block of the nucleic acid chains DNA or RNA. A nucleotide consists of a base (adenine, thymine, guanine, cytosine, or uracil) plus a sugar molecule (ribose or deoxyribose) and phosphate groups(s).

Nucleotides


Nucleotides: plural of nucleotide; building blocks of the nucleic acid chains DNA or RNA. Nucleotides consist of a base (adenine, thymine, guanine, cytosine, or uracil) plus a sugar molecule (ribose or deoxyribose) and phosphate group(s).

Nucleus


Nucleus is a noun with many meanings. A nucleus is a core around which other things cluster. In science, a nucleus is the part of a eukaryotic cell that contains the chromosomes; is a cluster of nerve cells with a specific function; is the centre of an atom made up mainly of protons and neutrons around which electrons cluster.

Nummular


Nummular is an adjective pertaining to a coin, such as being coin-shaped.

Nummular lesion


Nummular lesion, also called a discoid lesion, is a round, coin-shaped lesion.

Nummular lesions


Nummular lesions: plural of nummular lesion; lesions that are coin-shaped, round, or discoid.

O


Obsessive


Obsessive is an adjective pertaining to obsession, a preoccupation.

Obsessive-compulsive disorder


Obsessive compulsive disorder is characterised by obsessive and repetitive thoughts, images or urges with compulsions consisting of repetitive rituals and behaviours; these are performed to excess to reduce anxiety and distress related to their obsessions.

Occipital


Occipital is an adjective pertaining to the occiput, the back of the head. In surface anatomy it is used to describe the back of the head overlying the occipital bone.

Occluded


Occluded is an adjective and verb pertaining to occlusion, a block, blocked, to block.

Occlusion


Occlusion is the process of closing, blocking, or sealing. In medicine, occlusion may relate to a blood vessel, hollow organ or surface.

Occlusive


Occlusive is an adjective and noun pertaining to occlusion, the blocking, clogging, or sealing of a tube or surface.

Occlusives


Occlusives are oily substances that prevent evaporative moisture loss from the stratum corneum. Examples include vegetable or animal oils, waxes, fatty acids or alcohols, and hydrocarbons such as petrolatum.

OCD


OCD is the acronym for obsessive-compulsive disorder; obsessive and repetitive thoughts, images or urges with compulsions consisting of repetitive rituals and behaviours; these are performed to excess to reduce anxiety and distress related to their obsessions.

Ocular


Ocular is an adjective pertaining to the eye, so describes being related to or affecting the eye.

Odontogenic


Odontogenic: adjective pertaining to the tooth-forming tissue.

Odontogenic keratocyst


Odontogenic keratocyst: a congenital, benign but locally aggressive tumour in the jaw derived from the cells that formed the dental lamina.

Oedema


Oedema (American spelling edema) is tissue swelling due to excess interstitial fluid.

Oedematous


Oedematous (American spelling edematous) is an adjective pertaining to oedema, tissue swelling with fluid.

Oesophageal


Oesophageal (American spelling esophageal) is an adjective pertaining to the oesophagus, the gullet.

Oesophagitis


Oesophagitis (American spelling esophagitis) is inflammation of the oesophagus (gullet).

Oesophagus


Oesophagus (American spelling esophagus) is the muscular swallowing tube connecting the throat to the stomach, the gullet.

Oestrogen


Oestrogen (American spelling estrogen) is a steroid sex hormone produced mainly in the ovaries with important roles in the sexual development of a female amongst many others.

Oestrogens


Oestrogens: plural of oestrogen; (American spelling estrogens/estrogen); a class of steroid sex hormones produced naturally in the ovaries and synthetically for use in medications.

Oil drop


Oil drop is a nail sign, also called a salmon patch, in psoriasis presenting as an orange or brown streak or spot under the nail plate due to white cells in the nail bed.

Ointment


Ointment is a semi-solid formulation for topical use based on lipids (oils) and so tends to have a greasy feel. The lack of water in the formulation means preservatives are rarely required.

Oligoarthritis


Oligoarthritis refers to pain and swelling of a few joints. There are various kinds of arthritis.

Oncogene


Oncogene is a gene that codes for a protein that can promote the growth and proliferation of tumour cells.

Oncogenes


Oncogenes: plural of oncogene; genes that code for proteins that can promote the growth and proliferation of tumour cells.

Oncogenic


Oncogenic is an adjective pertaining to the triggering or development of a cancer. Common usage applies this to viruses that can trigger cancer such as oncogenic human papillomaviruses, and cancer-promoting processes involving oncogenes.

Oncoprotein


Oncoprotein is the protein product of an oncogene that promotes tumour formation or growth. An oncoprotein may act in the nucleus, cytoplasm, membranes or on the outside of a cell to cause unregulated cell growth.

Oncoproteins


Oncoproteins: plural of oncoprotein; protein products of oncogenes that promote tumour formation or growth.

Onychauxis


Onychauxis is the thickening or hypertrophy of the nail plate due to subungual scale.

Onychia


Onychia is inflammation of the nail matrix.

Onychocryptosis


Onychocryptosis is an in-growing nail.

Onychocyte


Onychocyte is a specialised keratinocyte (skin cell) that forms the nail plate.

Onychocytes


Onychocytes: plural of onychocyte; specialised keratinocytes (skin cells) that form the nail plate.

Onychogryphosis


Onychogryphosis is a thick, yellow-brown, hard nail plate curved in the shape of a ram's horn, usually seen affecting the great toenail in the elderly.

Onycholysis


Onycholysis is the abnormal lifting of the nail plate from the distal nail bed, presenting as a larger than normal white or yellow area at the end of a nail plate.

Onychomadesis


Onychomadesis is nail shedding (loss of nail) due to proximal detachment.

Onychorrhexis


Onychorrhexis is longitudinal ridging and fissuring of the nail plate typically seen with ageing and diffuse nail matrix diseases.

Onychoschizia


Onychoschizia, also called lamellar dystrophy, is the horizontal splitting of the distal nail plate into multiple layers, usually due to dehydration of the nail from water or detergent damage.

Oocysts


Oocysts: plural of oocyst; fertilised egg stage of development in the lifecycle of a protozoan.

Open-label


Open-label is an adjective used to describe clinical trials in which both the participants and researchers know which treatment or intervention is selected for the participant.

Ophthalmological


Ophthalmological is an adjective pertaining to ophthalmology, the study of the eye, its examination, conditions, and treatment.

Ophthalmologist


Ophthalmologist is a medical and surgical specialist who diagnoses and treats diseases of the eye.

Ophthalmology


Ophthalmology is the study of the eyes, their function, conditions, diseases, and treatments.

Orchitis


Orchitis is inflammation of the testes (testicle).

Organelle


Organelle is a structurally discrete component of a cell that has a specific function.

Organelles


Organelles: plural of organelle; structurally discrete components of cells that have specific functions.

Organism


Organism is any living entity such as an animal, plant, fungus, or bacterium.

Organisms


Organisms: plural of organism; any forms of life, including animals, plants, fungi, or bacteria.

Organogenesis


Organogenesis is the formation and development of organs.

Organomegaly


Organomegaly literally means big organ, so is used to describe any enlarged organ in the body such as the liver or spleen.

Oropharyngeal


Oropharyngeal is an adjective pertaining to the oropharynx, the back part of the throat that includes the back of the tongue, the soft palate and the tonsils.

Oropharynx


Oropharynx is the back part of the throat, comprising the back of the tongue, the soft palate, and the tonsils.

Orthokeratosis


Orthokeratosis is a histological term for the normal stratum corneum consisting of keratinised cells not containing nuclei.

Orthopaedic


Orthopaedic (American spelling orthopedic) is an adjective pertaining to orthopaedics, the branch of surgery dealing with bones and muscles.

Orthopaedics


Orthopaedics (American spelling orthopedics) is the branch of surgery dealing with bones and muscles.

Osmotic pressure


Osmotic pressure: is the pressure required to prevent movement of a solution or solvent across a semi-permeable membrane. It is a water-pulling force.

Osteoarthritis


Osteoarthritis is a degenerative joint disease.

Osteomyelitis


Osteomyelitis is a bacterial infection in bone.

Osteotomy


Osteotomy: surgical procedure involving the cutting and reshaping of bone.

OTC


OTC is the acronym for 'over-the-counter', an adjective used in healthcare to describe a therapeutic product that can be purchased without a doctor's prescription.

Otitis


Otitis is inflammation of the ear.

Otitis media


Otitis media is inflammation of the middle ear.

Over the counter


Over the counter (acronym OTC) is an adjective used in healthcare to describe a therapeutic product that can be purchased without a doctor's prescription.

Over-the-counter


Over-the-counter (acronym OTC) is an adjective used in healthcare to describe a therapeutic product that can be purchased without a doctor's prescription.

Oxidation


Oxidation is the loss of an electron(s) by a molecule, atom or ion during a chemical reaction resulting in a positive charge. It is the opposite of reduction (the gaining of electrons).

P


Pachymeningitis


Pachymeningitis is inflammation of the outer membrane (dura) of the brain or spinal cord.

Pachyonychia


Pachyonychia means elephant nail, and is a congenital abnormal thickening of nail.

Paediatric


Paediatric (American spelling pediatric) is an adjective pertaining to paediatrics, the medical and surgical care of infants, children, and adolescents.

Paediatrics


Paediatrics (American spelling pediatrics) is the medical speciality caring for infants, children and adolescents.

Pagetoid


Pagetoid is an adjective used in histology to describe a resemblance to Paget cells, their appearance or behaviour. Paget cells are large pale cells seen the epidermis in Paget disease.

Palate


Palate: the roof of the mouth; composed of the hard and soft palate.

Pallor


Pallor is an unusual pale appearance. Pallor may be used to describe paleness clinically of the skin or conjunctivae, or in histology, eg, epidermal pallor.

Palmar


Palmar is an adjective pertaining to the palm of the hand.

Palmoplantar


Palmoplantar is an adjective pertaining to the palms and soles.

Palpable


Palpable is an adjective pertaining to palpation, to be obvious by touch.

Palpation


Palpation is the process of feeling or touching.

Pancreatitis


Pancreatitis is inflammation of the pancreas.

Panniculitis


Panniculitis is inflammation of the subcutaneous fat.

Panniculus


Panniculus means a layer of tissue. In common usage, panniculus refers to the layer of subcutaneous fat.

Panuveitis


Panuveitis is widespread inflammation of the uveal tract of the eye, including the iris and the choroid.

Papilla


Papilla is a small nipple-shaped protuberance. There are several types of papilla on the tongue surface.

Papillae


Papillae: plural of papilla; nipple-shaped protruberances. Papillae cover the tongue surface.

Papillary dermis


Papillary dermis is the upper portion of the dermis just beneath the epidermis. It consists of thin irregularly arranged collagen fibres, thin elastic fibres and ground substance.

Papilloma


Papilloma is a generic term for a benign tumour that arises in the epithelium (the skin and mucous membranes). Common usage of papilloma includes a skin tag and plantar wart.

Papillomas


Papillomas: plural of papilloma; a generic term for a benign tumours that arises in the epithelium (the skin and mucous membranes). Common usage of papillomas includes skin tags and plantar warts.

Papillomatosis


Papillomatosis is a histological term for irregular, undulating, folding of the epidermal surface.

Papillomatous


Papillomatous is an adjective pertaining to a papilloma. Clinically it describes the bumpy elevated surface of a lesion such as a viral wart. Histologically papillomatous describes irregular surface folding.

Papular


Papular is an adjective pertaining to papules, small raised palpable lesions.

Papule


Papule is an elevated, solid, palpable lesion that is less than 1 cm in diameter.

Papules


Papules: plural of papule; elevated, solid, palpable lesions that are less than 1 cm in diameter.

Papulopustular


Papulopustular is an adjective describing the presence of both papules and pustules.

Papulopustule


Papulopustule is a skin lesion with both papular and pustular components.

Papulopustules


Papulopustules: plural of papulopustule; skin lesions with both papular and pustular components.

Papulosquamous


Papulosquamous is an adjective describing being scaly, raised and palpable, as in papules and plaques.

Papulovesicle


Papulovesicle is a skin lesion with both papular (small bumps) and vesicular (small blisters) components, typically a small bump with a tiny blister on top as seen in an insect bite.

Papulovesicles


Papulovesicles: plural of papulovesicle; lesions with both papular (small bumps) and vesicular (small blisters) components.

Papulovesicular


Papulovesicular is an adjective pertaining to the presence of both papules (small bumps) and vesicles (small blisters) in a lesion or rash.

Paraesthesia


Paraesthesia (American spelling paresthesia) literally means an abnormal (para) sensation (esthesia), and is usually neurological in origin. In the skin, paraesthesia includes positive symptoms such as pruritus (itch), burning, crawling, stinging, hyperaesthesia, allodynia, and pain; and negative symptoms such as anaesthesia (numbness) or a cold sensation. The most common form of cutaneous paraesthesia is 'pins and needles'.

Paraesthesias


Paraesthesias: plural of paraesthesia; (American spelling paresthesias/paresthesia); abnormal sensations usually neurological in origin.

Parakeratosis


Parakeratosis is a histological word for an abnormal stratum corneum in which the keratinised cells of the skin surface retain their nuclei.

Parakeratotic


Parakeratotic is an adjective used in histology pertaining to parakeratosis; retention of nuclei in the stratum corneum of the epidermis.

Paralysis


Paralysis is the inability to move part of the body.

Paraneoplastic


Paraneoplastic is an adjective describing being remote to but associated with a neoplasm. A paraneoplastic symptom or sign indicates the presence of an internal cancer.

Paraprotein


Paraprotein, also called M-protein, is a monoclonal immunoglobulin found in the blood or urine, a marker of a monoclonal gammopathy.

Paraproteinaemia


Paraproteinaemia (American spelling paraproteinemia) is the presence of a monoclonal immunoglobulin in the blood due to a monoclonal gammopathy.

Paraproteins


Paraproteins: plural of paraprotein; monoclonal immunoglobulins found in the blood or urine, a marker of monoclonal gammopathies.

Parasite


Parasite: an organism that cannot live independently of a living host.

Parasites


Parasites: plural of parasite; an organism that cannot live independently of a living host.

Parasitic


Parasitic: adjective pertaining to an organism that cannot live independently of a living host.

Parasympathetic innervation


Parasympathetic innervation involves two neurones connecting specific nuclei in the central nervous system to the end organ. The cranial parasympathetic nerves innervate the eyes and salivary glands; the vagus nerve innervates the heart, lungs and digestive tract as far as the midgut; the pelvic splanchnic nerves innervate the hindgut, urinary system, and sexual organs.

Parasympathetic nerves


Parasympathetic nerves are the final connector of the parasympathetic nervous system between ganglia close to the end organ and the end organs to cause those involuntary changes required for relaxation, digestion, and sexual arousal. Cranial nerves III, VII, IX and X and sacral nerves S2-4 are parasympathetic nerves.

Parasympathetic nervous system


Parasympathetic nervous system is the division of the involuntary autonomic nervous system involved in relaxation, digestion, urination, and sexual arousal. Stimulation of the parasympathetic nervous system slows heart and respiratory rates, dilates blood vessels and lowers blood pressure, promotes digestion and urination, and causes sexual arousal.

Paronychia


Paronychia literally means around the nail, and is an inflammatory process around the edge of a nail.

Parotid gland


Parotid gland is the large salivary gland found just in front of the ear.

Parotid glands


Parotid glands: plural of parotid gland; the pair of large salivary glands found just in front of the ears.

Paroxysmal


Paroxysmal is an adjective describing periodic episodes of a symptom or sign.

Parturition


Parturition is the process of childbirth.

PASI


PASI is the acronym for Psoriasis Area and Severity Index, and is used for assessment and monitoring of psoriasis.

Paste


Paste is a semi-solid formulation for topical application, comprised mostly of a powder such as zinc oxide. The powder is mixed with water or oil in varying proportions to form either a greasy protective fatty paste that is very stiff, or a drying cooling paste that tends to be soothing. Medicaments may be added to the paste, eg, dithranol in Lassar paste in the Ingram regime.

Patch


Patch refers to a large area of colour change, > 1 cm in diameter, usually with a smooth surface.

Pathergy


Pathergy is the development or flare of skin lesions after minor trauma, such as a needle prick, typically seen in Behcet disease and pyoderma gangrenosum.

Pathogen


Pathogen is an organism that can cause disease. Examples of a pathogen may include a virus, protozoan, or yeast.

Pathogenesis


Pathogenesis is the origin, development, and maintenance of a disease.

Pathogenic


Pathogenic is an adjective pertaining to pathogenesis, the cause of disease. It usually refers to microorganisms, eg, a pathogenic virus is one that causes disease.

Pathogens


Pathogens: plural of pathogen; organisms that causes disease. Microorganisms such as bacteria, viruses, and fungi are examples of pathogens.

Pathognomonic


Pathognomonic is an adjective meaning characteristic or distinctive. A pathognomonic symptom or sign is one so distinctive that it can be used to make a diagnosis.

Pathologic


Pathologic is an adjective pertaining to pathology, the study of the causes and effects of disease. Pathologic can therefore be used to describe the investigation of, association with, or causation of disease.

Pathological


Pathological is an adjective pertaining to pathology, the study of the causes and effects of disease. Pathological can therefore be used to describe the investigation of, association with, or causation of disease.

Pathological examination


Pathological examination is the investigation of a tissue by a pathologist.

Pathologist


Pathologist is a medical specialist in the study of pathology; the practice of performing and interpreting diagnostic tests using materials removed from living or dead patients.

Pathology


Pathology is the study of the causes and effects of disease, often used to describe medical science undertaken in a laboratory.

Pathophysiological


Pathophysiological is an adjective pertaining to pathology and physiology; abnormal function resulting in a condition or disease.

Pathophysiology


Pathophysiology is the study of the functional changes in living tissue in a particular medical condition.

Paucibacillary


Paucibacillary is an adjective meaning few or no bacteria.

PCR


PCR is the acronym for polymerase chain reaction. PCR is used for the detection and amplification of specific DNA sequences useful in making a diagnosis and gene sequencing.

Peduncle


Peduncle is a stalk-like component of a lesion.

Peduncles


Peduncles: plural of peduncle; stalks of lesions.

Pedunculated


Pedunculated is an adjective pertaining to a peduncle, a stalk.

Penetrance


Penetrance is used in genetics to mean the frequency a heritable trait is manifested by the individuals that carry it. A genetic mutation with high penetrance has a high frequency of expression on phenotypic examination of a population.

Peptide


Peptide is a short chain of amino acids, shorter than a protein.

Peptides


Peptides: plural of peptide; short chains of amino acids, shorter than proteins.

Perforate


Perforate is a verb meaning to make holes.

Perforating


Perforating is a verb and adjective pertaining to perforation, penetration, the making of holes. In dermatology, perforating also describes conditions in which something penetrates through a layer as in a perforating dermatosis.

Perforation


Perforation is a hole (or series of holes) made by piercing. In medicine perforation refers to a hole in the wall of an organ either from disease, eg, perforation of the stomach due to a gastric ulcer, or due to trauma, eg, a knife wound may cause a perforation in the bowel.

Perforations


Perforations: plural of perforation; holes made by piercing.

Perfuse


Perfuse is a verb meaning to flow or spread a fluid such as blood or saline.

Perfused


Perfused can be used as a verb or adjective pertaining to perfusion, the process of passing fluid though spaces and blood vessels.

Perfusion


Perfusion is the process of passing fluid through spaces including blood vessels.

Peri-adnexal


Peri-adnexal is an adjective meaning to be around an adnexa(e), an extra structure such as a hair follicle in the skin.

Peri-anal


Peri-anal is an adjective pertaining to the area around the anus.

Peri-orificial


Peri-orificial is an adjective pertaining to the area close-to or around an orifice such as the mouth, eyes, or anus.

Periadnexal


Periadnexal is an adjective to describe being around an adnexa(e). In the skin, periadnexal would be used to describe changes around the pilosebaceous structures, sweat or scent glands.

Perianal


Perianal is an adjective pertaining to the area around the anus.

Pericarditis


Pericarditis is inflammation of the pericardium, the membrane that surrounds and encloses the heart.

Perifollicular


Perifollicular is an adjective meaning close-to or surrounding a hair follicle(s).

Perifolliculitis


Perifolliculitis is inflammation close-to and around hair follicles.

Perilesional


Perilesional is an adjective to describe being close-to or around a lesion.

Perinasal


Perinasal is an adjective pertaining to the area around the nose.

Perineal


Perineal is an adjective pertaining to the perineum, the area between the anus and either the posterior fourchette of the vagina or the scrotum.

Perineum


Perineum in the female is from the anus to the posterior fourchette of the vulva. In the male it is the area between the anus and scrotum. Common usage has widened use to include the perianal skin, groin folds, and vulva or scrotum.

Perineural


Perineural is an adjective pertaining to the area around a nerve.

Perinuclear


Perinuclear is an adjective pertaining to the area close-to or around the nucleus.

Periocular


Periocular is an adjective pertaining to the area close-to and around the eye.

Periodontitis


Periodontitis is inflammation of the periodontium, the supporting tissues around the tooth which comprise the alveolar bone, the gums, and the periodontal ligament.

Perioral


Perioral is an adjective pertaining to the area close-to and around the mouth.

Periorbital


Periorbital is an adjective to describe being around the orbit or the eye.

Periorificial


Periorificial is an adjective pertaining to the area close-to or around an orifice such as the mouth, eyes, or anus.

Peripheral


Peripheral is an adjective pertaining to the outer edge.

Peritoneal


Peritoneal is an adjective pertaining to the peritoneum, the membrane that lines the inner surface of the abdominal cavity and covers the abdominal organs.

Peritoneum


Peritoneum is the membrane that lines the inner surface of the abdominal cavity and covers the abdominal organs.

Periungual


Periungual is an adjective pertaining to around a fingernail or toenail.

Perivascular


Perivascular is an adjective used in histology meaning close-to and around blood vessels.

Permeability


Permeability is the property of allowing diffusion, transit or passing through, porosity, eg, the permeability of a membrane.

Permeable


Permeable is an adjective pertaining to passing or diffusing through, eg, a permeable membrane allows passage through.

Permeate


Permeate is a verb meaning to diffuse through.

Persist


Persist is a verb meaning to persevere, to continue or remain for a prolonged period.

Persistence


Persistence is perseverence, a noun for continuing or remaining for a prolonged time.

Persistent


Persistent is an adjective pertaining to continuing or remaining for a prolonged time.

PET


PET is the acronym for positron emission tomography; a nuclear medicine imaging test using a radiotracer to assess tissue metabolism.

Petechia


Petechia is a pinpoint form of purpura, presenting as a red, purple or brown, non-blanchable spot,

Petechiae


Petechiae: plural of petechia; pinpoint form of purpura presenting as red, purple or brown non-blanchable spots,

Petechial


Petechial is an adjective pertaining to petechiae, pinpoint purpura due to red blood cell leakage from capillaries.

Petechial haemorrhage


Petechial haemorrhage is leakage of red blood cells from a capillary presenting as a pinpoint purpura.

Petechial haemorrhages


Petechial haemorrhages are pinpoint purpura due to red blood cell leakage from capillaries.

pH


pH is a log scale defining hydrogen ion concentration and hence acidity/alkalinity in a solution. The scale ranges from 0 to 14, with 0 as most acidic and 14 as most alkaline. Water is pH 7, defined as a neutral solution.

Phagocyte


Phagocyte is an immune cell that can surround, kill and ingest particles such as bacteria and other microorganisms or foreign matter, a process is called phagocytosis. A phagocyte can also boost immune responses. Examples of a phagocyte include a macrophage and neutrophil.

Phagocytes


Phagocytes: plural of phagocytes; immune cells that can engulf foreign matter by phagocytosis. Macrophages and neutrophils are examples of phagocytes.

Phagocytic


Phagocytic is an adjective pertaining to phagocytosis, the process by which a cell engulfs and ingests a particle.

Phagocytosis


Phagocytosis is the process by which a cell engulfs and ingests a particle.

Phalangeal


Phalangeal is an adjective pertaining to phalanges, the long bones in fingers and toes.

Phalanges


Phalanges: plural of phalanx; the long bones of the fingers and toes.

Phalanx


Phalanx is the long bone of the fingers and toes.

Pharmacodynamic


Pharmacodynamic is an adjective pertaining to pharmacodynamics, the mechanisms of action of a drug.

Pharmacodynamics


Pharmacodynamics is the study of drug mechanisms of action.

Pharmacokinetic


Pharmacokinetic is an adjective pertaining to pharmacokinetics, the science of drug absorption, distribution, metabolism, and excretion.

Pharmacokinetics


Pharmacokinetics is the science of the absorption, distribution, metabolism and excretion (ADME) of drugs.

Pharnygeal


Pharyngeal is an adjective pertaining to the pharynx, the muscular tube connecting the nose and mouth to the larynx and oesophagus.

Pharyngitis


Pharyngitis is inflammation of the pharynx, usually presenting as a sore throat.

Pharynx


Pharynx is the muscular tube connecting the nose and mouth to the larynx (and lungs), and the oesophagus (and stomach).

Phenotype


Phenotype is the expression of an observable trait, characteristic or form resulting from genetic and environmental influences.

Phenotypes


Phenotypes: plural of phenotype; the expressions of observable traits, characteristics or forms resulting from genetic and environmental influences.

Phenotypic


Phenotypic is an adjective pertaining to phenotype, the observable characteristics and physical form.

Pheromone


Pheromone is a chemical messenger excreted onto the body surface to signal to other members of the same species.

Pheromones


Pheromones: plural of pheromone; chemical messengers excreted onto the body surface to signal to other members of the same species.

Phlebectasia


Phlebectasia is the congenital widening (dilation) of a vein.

Phosphatase


Phosphatase is an enzyme that releases a phosphate group from a molecule, a process called dephosphorylation.

Photoageing


Photoageing (American spelling photoaging) is an acceleration of the skin changes of ageing caused by exposure to ultraviolet radiation especially sunlight.

Photoaging


Photoaging (British spelling photoageing) is an acceleration of the skin changes of ageing caused by exposure to ultraviolet radiation especially sunlight.

Photoallergen


Photoallergen is a substance that causes an allergic reaction to sunlight after either topical contact or systemic exposure. A photoallergen may be a medication, food, plant, or other chemical.

Photoallergic


Photoallergic is an adjective pertaining to photoallergy; a delayed hypersensitivity reaction to a substance in the presence of light.

Photoallergy


Photoallergy is a delayed hypersensitivity reaction to a substance after exposure to light. It can be due to topical or systemic contact with a photoallergen or photosensitiser such as a medication, plant or food.

Photodermatitis


Photodermatitis is an eczematous reaction caused or aggravated by exposure to light.

Photodynamic


Photodynamic is an adjective pertaining to the activation or intensification of a reaction by exposure to light in a living system, eg, photodynamic therapy (PDT) applies a topical photosensitiser to increase the reaction to a laser or light.

Photophobia


Photophobia is an abnormal aversion to light.

Photoprotection


Photoprotection is the process of using physical or chemical agents to protect against light, eg, UPF50+ clothing and SPF50+ sunscreens provide photoprotection.

Photoprotective


Photoprotective is an adjective pertaining to photoprotection, the process of protecting against the adverse effects of light.

Photosensitive


Photosensitive is an adjective pertaining to photosensitivity, an unusual sensitivity to light, including sunlight.

Photosensitivity


Photosensitivity is an unusual increase in the reactivity of the skin to sunlight.

Photothermolysis


Photothermolysis means using light (photo) to heat (thermo) a selected area for destruction (lysis).

Phototoxic


Phototoxic is an adjective pertaining to phototoxicity; a dose-related chemical-induced sensitivity to light that does not involve an immune reaction.

Phototoxicity


Phototoxicity is a dose-related chemical-induced sensitivity to light that does not involve an immune reaction.

Physiological


Physiological is an adjective pertaining to physiology, the study of the normal function of cells, tissues, or the organism as a whole.

Physiology


Physiology is the study of the normal function of cells, tissues, or the organism as a whole.

Pigment


Pigment is a coloured chemical. Pigment in the skin may be endogenous such as melanin or bilirubin in jaundice, or exogenous eg, from medications or tattoos. To pigment is also a verb meaning to colour.

Pigmentary


Pigmentary is an adjective pertaining to pigment, a coloured chemical.

Pigmentation


Pigmentation is colour. The pigmentation of human skin is a mix of natural colours such as melanin and haemoglobin, ingested colours including carotene or silver, or exogenous colours as in tattoos.

Pigmented


Pigmented is an adjective to describe being coloured. Human skin may be naturally pigmented due to melanin and haemoglobin, ingested colours such as carotene or silver, or exogenous colours as in tattoos.

Pilosebaceous


Pilosebaceous is an adjective pertaining to the pilosebaceous unit, a structure consisting of a hair follicle and sebaceous (oil) gland.

Pilosebaceous structure


Pilosebaceous structure consists of a hair follicle and sebaceous (oil) gland.

Pilosebaceous structures


Pilosebaceous structures consist of a hair follicle and sebaceous (oil) gland. Apocrine glands and arrector pili muscles may also be attached to the hair follicle.

Pilosebaceous unit


Pilosebaceous unit consists of a hair follicle and sebaceous (oil) gland.

Pit


Pit is a depression, hole or indentation in a surface. To pit is also a verb, meaning to remove the stone of a fruit.

Pitting


Pitting is an adjective pertaining to pits, tiny depressions or indentations in a surface, eg, pitting oedema. Common usage also makes pitting a noun, as in the nail pitting of psoriasis.

Pitting oedema


Pitting oedema (American spelling edema) is the accumulation of interstitial fluid in tissues to such as extent that pressure causes an indentation (pit) that resolves after releasing the pressure.

Pituitary


Pituitary is an adjective pertaining to the pituitary gland in the brain, eg, a pituitary hormone. Common usage also makes pituitary a noun, ie, the pituitary (gland).

Pituitary gland


Pituitary gland is a small organ in the base of the brain that produces many hormones. It is divided into the anterior lobe and the posterior lobe of the pituitary gland.

Pityriasis


Pityriasis is an adjective meaning finely scaly, and is used to describe a bran-like fine powdery scale.

Placebo


Placebo is a substance with no known therapeutic effect or, in a placebo-controlled drug-trial, contains all the ingredients except for the active ingredient (drug) being tested.

Placebo effect


Placebo effect is an apparent response to a substance with no known therapeutic effect.

Placebos


Placebos: plural of placebo; substances with no known therapeutic effect, or in placebo-controlled drug trials, placebos will contain all the ingredients except for the drug being tested.

Placenta praevia


Placenta praevia is a condition in which the placenta is located over the neck of the uterus (womb) or cervix, interfering with normal vaginal delivery of the baby.

Plantar


Plantar is an adjective pertaining to the sole of the foot.

Plaque


Plaque is a circumscribed, palpable lesion more than 1 cm in diameter. A plaque may be visibly elevated above the skin or a palpably thickened lesion in the skin.

Plaques


Plaques: plural of plaque; circumscribed, palpable lesions more than 1 cm in diameter; plaques may be visibly elevated above the skin surface or thickened lesions in the skin.

Plasma


Plasma is the fluid component of blood or lymph, ie, that part of blood or lymph without the cells. Plasma is also a state of matter initially thought to only occur at extremely high temperatures but cold plasma has now been developed for use in medicine, eg, non-laser plasma skin rejuvenation. Plasma is also an adjective to describe a cell type, ie, plasma cell, an activated form of B-cell.

Plasma cell


Plasma cell is an activated tissue B lymphocyte (B cell) producing immunoglobulin in an immune response.

Plasma cells


Plasma cells are activated tissue B lymphocytes (B cells) producing immunoglobulins in an immune response.

Platelet


Platelet, also known as a thrombocyte, is a tiny fragment of a megakaryocyte, a bone marrow cell, involved in blood clotting. A platelet does not have a nucleus.

Platelets


Platelets: plural of platelet; also called thrombocytes; tiny fragments derived from megakaryocytes in the bone marrow, and involved in blood clotting. Platelets lack nuclei.

Pleomorphic


Pleomorphic is an adjective pertaining to pleomorphism, many shapes or forms; Pleomorphic is used in histology to describe wide variability in the morphology of cells or nuclei.

Pleomorphism


Pleomorphism is multiple different forms. It is commonly used in histology to mean wide variability in nuclear or cell morphology which typically indicates malignancy.

Pleura


Pleura is the membrane around the outside of a lung and lining the chest cavity.

Pleurae


Pleurae: plural of pleura; the membranes enclosing the lungs and lining the chest cavity.

Pleural


Pleural is an adjective pertaining to the pleura, a membrane enclosing a lung and lining the chest cavity.

Pleural cavity


Pleural cavity is the space lined by a pleural membrane, located between the lungs and the chest wall.

Pleural effusion


Pleural effusion is the accummulation of fluid in the pleural cavity between a lung and the chest wall.

Pleural effusions


Pleural effusions: plural of pleural effusion; accummulation of fluid in the pleural cavities between the lungs and the chest wall.

Pleurisy


Pleurisy is inflammation of the pleura, the membrane enclosing a lung and lining the chest cavity.

Plexiform


Plexiform is an adjective pertaining to a plexus, a complex network or web, eg, a plexiform neuroma.

Plexus


Plexus is a braid or tangled network. In medicine it is used for a network of nerves or vessels, eg, the brachial plexus.

Plexuses


Plexuses: plural of plexus; braids or networks of vessels or nerves.

Plicated


Plicated is an adjective pertaining to folding or tucking.

Pneumonitis


Pneumonitis is inflammation of the lung.

Pneumothorax


Pneumothorax is air in the pleural cavity, ie, the chest cavity outside the lung.

Poikiloderma


Poikiloderma is skin with a variegated mottled appearance, typically consisting of epidermal atrophy, telangiectasia, and hypo- or hyper-pigmentation.

Poliosis


Poliosis is a patch of depigmentated hair.

Polyarthralgia


Polyarthralgia means multiple painful joints.

Polyarthritis


Polyarthritis is inflammatory arthritis affecting many joints (five or more).

Polycyclic


Polycyclic is an adjective describing many circles, which may be used in dermatology to describe a rash composed of rings or partial ring-shaped lesions.

Polycythaemia


Polycythaemia is an increased (excessive) number of red blood cells in the peripheral blood.

Polycythaemia vera


Polycythaemia vera, also known as polycythaemia rubra vera, is a chronic myeloproliferative disorder that results in an increased number of red cells in the peripheral blood.

Polydactyly


Polydactyly means many fingers, and describes having more than five fingers or toes on a hand or foot.

Polygonal


Polygonal is an adjective pertaining to many angles. A polygonal skin lesion has a non-geometric shape.

Polyhydraminos


Polyhydraminos: the excessive accumulation of amniotic fluid.

Polymerase chain reaction


Polymerase chain reaction (acronym PCR) is a laboratory tool for detecting and amplifying a specific DNA sequence. It is useful in making a diagnosis by detecting DNA sequences of viruses or bacteria such as HPV in cervical swabs or HSV in skin swabs.

Polymorphic


Polymorphic, also called polymorphous, is an adjective pertaining to multiple forms, eg, a polymorphic rash has many components.

Polymorphism


Polymorphism is many forms; in histology nuclear polymorphism means the cell nuclei are variable in shape or appearance, ie, many forms of the nucleus; in genetics a polymorphism is a chromosomal locus with more than two alleles in the general population, ie, many forms of the gene resulting in many forms of the protein product,ie, protein polymorphisms; a single nucleotide polymorphism (SNP) may change the pharmacodynamics or pharmacokinetics of a drug and hence the therapeutic response.

Polymorphisms


Polymorphisms: plural of polymorphism; many forms; in genetics polymorphisms are chromosomal loci with more than two alleles in the general population; single nucleotide polymorphisms (SNPs) can affect the pharmacokinetics and pharmacodynamics of a drug and hence the therapeutic effect.

Polymorphonuclear


Polymorphonuclear, literally means many forms of the nucleus, and is an adjective pertaining to an irregular lobulated nucleus, eg, polymorphonuclear leukocytes are granular immune cells with multilobed nuclei.

Polymorphous


Polymorphous, also called polymorphic, is an adjective to describe many forms. A rash may be described as being polymorphous if it has multiple presentations or multiple lesion types, eg, polymorphous light eruption.

Polymyalgia


Polymyalgia means multiple painful muscles.

Polyploid


Polyploid is an adjective describing a cell with more than the normal two sets of chromosomes, typically seen in malignant cells.

Polysaccharide


Polysaccharide is many sugar molecules bonded together to form one large carbohydrate molecule, a long chain of sugar molecules.

Polysaccharides


Polysaccharides: plural of polysaccharide; large carbohydrate molecules formed by the bonding together of many sugar molecules.

Pomade


Pomade is a greasy or waxy perfumed ointment or gel usually used to style scalp or facial hair.

Pomades


Pomades: plural of pomade; greasy or waxy ointments or gels used to style scalp or facial hair.

Popliteal


Popliteal is an adjective pertaining to the back of the knee; examples include the popliteal artery and popliteal fossa.

Porphyria


Porphyria is a disorder characterised by the abnormal accumulation and excretion of a porphyrin(s). A porphyria may be acquired or inherited.

Porphyrias


Porphyrias: plural of porphyria; disorders characterised by the abnormal accumulation and excretion of a porphyrin(s). Porphyrias may be inherited or acquired.

Porphyrin


Porphyrin is an example of an aromatic ring-shaped tetrapyrrole molecule. Tetrapyrroles form chlorophyll, haemoglobin and vitamin B12. Haem is a porphyrin molecule with iron inserted in the centre of the ring, whereas magnesium is in the centre in chlorophyll. Enzyme deficiencies can result in the accumulation of a porphyrin in blood, urine and faeces.

Porphyrins


Porphyrins: plural of porphyrin; aromatic ring-shaped tetrapyrroles. Tetrapyrroles form chlorophyll, haemoglobin and vitamin B12. Haem is a porphyrin molecule with iron inserted in the centre of the ring, whereas magnesium is in the centre in chlorophyll. Enzyme deficiencies can result in the accumulation of various porphyrins in blood, urine and faeces.

Positron emission tomography


Positron emission tomography (acronym PET scan) is a nuclear medicine imaging test used for assessing metabolic activity in tissues. Prior to imaging, a radiotracer is introduced into the body by one of a variety of routes including injection. In dermatology a PET scan may be used to detect skin cancer metastases or assess response to treatment.

Positron emission tomography (PET)


Positron emission tomography (PET) is a nuclear medicine imaging test used for assessing metabolic activity in tissues.

Post-inflammatory


Post-inflammatory literally means after inflammation, and is an adjective pertaining to changes after resolution of inflammation.

Postectomy


Postectomy or circumcision is the surgical removal of the penile foreskin.

 

Posterior


Posterior is an adjective meaning behind or towards the back. In anatomy a posterior location means on the back of a body part (dorsal).

Postinflammatory


Postinflammatory is an adjective pertaining to changes after resolution of inflammation.

Postnatal


Postnatal is an adjective meaning after birth, eg, postnatal depression.

Postpartum


Postpartum is the six week period after having a baby.

Powder


Powder is a pulverised solid, for example talc (a mineral) or corn starch (vegetable).

Pre-eclampsia


Pre-eclampsia is a complication of pregnancy, presenting with high blood pressure, oedema (swelling) and proteinuria.

Preauricular


Preauricular is an adjective pertaining to a location in front of the ear.

Precancerous


Precancerous, also called premalignant, is an adjective pertaining to a state prior to becoming a cancer or malignancy, eg, actinic keratosis and oral leukoplakia are regarded as precancerous lesions due to the risk of developing into squamous cell carcinomas.

Precipitate


Precipitate is a verb, noun, and adjective. Precipitate, the verb, means to come out of solution, to make something happen, or to fall from the clouds such as rain or snow. Precipitate is a noun used in chemistry for the solid material in a solution, eg, sugar forms a precipitate in the bottom of a hot drink as the fluid cools. Precipitate is an adjective pertaining to sudden or unexpected, eg, a precipitate decision.

Precipitated


Precipitated is the past tense of the verb meaning to come out of solution or to make something happen, or to fall from the clouds.

Precipitating


Precipitating is an adjective pertaining to a sudden development or event, eg, precipitating trigger for a disease or condition, or chemistry dissolution. Precipitating is also a verb often used to mean it is raining or snowing, or a solute is precipitating out of solution.

Predilection


Predilection is a preference.

Predispose


Predispose is a verb meaning to increase susceptibility to a disease or condition.

Predisposition


Predisposition is the susceptibility to a disease or condition.

Premalignant


Premalignant, also called precancerous, is an adjective meaning before malignant; a stage before becoming cancerous.

Premastication


Premastication: the process of chewing food (mastication) before feeding it to another.

Premenopausal


Premenopausal: adjective pertaining to a woman between menarche (onset of menstrual periods at puberty) and menopause (end of menstrual periods in middle age).

Premenstrual


Premenstrual: adjective pertaining to the few days prior to the onset of menstrual flow (period).

Prenatal


Prenatal, also called antenatal, is an adjective meaning before birth, eg, prenatal diagnosis.

Pretibial


Pretibial is an adjective pertaining to the tibia, the bone forming the shin.

Prevalence


Prevalence is the total number of cases of a particular disease or condition in a population at a specific time point. Prevalence is affected by both the incidence and chronicity of a disease or condition.

Prevalent


Prevalent is an adjective pertaining to prevalence; generally used to mean widespread or dominant.

Prickle cell layer


Prickle cell layer of the epidermis (stratum spinosum, spinous cell layer) is so-called because the prominent adherence plates (desmosomes) make the keratinocytes look spiny.

Primary


Primary is an adjective meaning first, and is used in many situations in medicine. A primary cancer is where the cancer first develops, compared to a secondary metastasis. Primary symptoms or signs are the first presentations of a disease or condition. Primary can also be used to describe a condition that is not secondary to something else, eg, primary versus secondary hypertension.

Prodromal


Prodromal is an adjective pertaining to prodrome, a warning or premonition. In medicine it decribes those symptoms or signs that warn of the impending illness.

Prodrome


Prodrome literally means running before, so is a premonitory (warning) symptom or sign of disease. The symptoms and signs that warn of an impending illness.

Prodromes


Prodromes: plural of prodrome; premonitory symptoms or signs of disease.

Progeny


Progeny is a singular and plural noun for offspring or descendants.

Progesterone


A steroid hormone released by the corpus lutem after ovulation that prepares the uterus for pregnancy.

Progesterones


Progesterones: plural of progesterone; a class of steroid sex hormones produced naturally by the ovary and placenta, and synthetically for medications with progesterone-like activity.

Progestin


Progestin is a synthetic form of the hormone progesterone for use in medications. Progestin has weak anti-androgen activity.

Progestins


Progestins: plural of progestin; synthetic forms of the hormone progesterone for use in medications. Progestins have weak anti-androgen effects.

Prognosis


Prognosis means the likely or expected course or outcome of a condition.

Prognostic


Prognostic is an adjective pertaining to prognosis, the likely or expected outcome or course of a condition.

Progress


Progress is a noun and verb pertaining to progression. Progress can mean an advance or advancement, advancing or developing. Examples include the progress of a patient in hospital (noun), the condition can progress to something worse (verb).

Progressive


Progressive is an adjective pertaining to progression, an advance or advancement, In medicine a progressive condition deteriorates or worsens.

Proinflammatory


Proinflammatory is an adjective pertaining to the promotion of tissue inflammation.

Prokaryote


Prokaryote is a cellular organism in which the genetic material is free in the cytoplasm as there is no nucleus.

Proliferating


Proliferating is an adjective pertaining to proliferation, the growth and reproduction of similar cells or organisms, eg, proliferating melanocytes.

Proliferation


Proliferation is the process of increasing; proliferation can be used in biology for the growth and reproduction of similar cells or organisms, eg, vascular proliferation, proliferation of malignant cells.

Proliferations


Proliferations: plural of proliferation; clusters of similar growing and dividing cells or structures.

Proliferative


Proliferative is an adjective pertaining to proliferation, the growth and reproduction of cells, eg, proliferative haemangiomas.

Prophylactic


Prophylactic is an adjective pertaining to prophylaxis, an action to prevent a development or deterioration.

Prophylactically


Prophylactically is an adverb pertaining to prophylaxis, to prevent the development or deterioration of an event.

Prophylaxis


Prophylaxis is an action to prevent a development or deterioration.

Proptosis


Proptosis is the abnormal protrusion of the eyeball.

Protease


Protease is an enzyme that splits or breaks down proteins.

Protease inhibitor


Protease inhibitor, also called an antiprotease, is a naturally occurring molecule that inhibits protease enzymes, for example alpha-1 anti-trypsin. Also a class of antiviral drug that inhibit viral protease used to treat viral infections such as human immunodeficiency virus (HIV) and hepatitis C.

Protease inhibitors


Protease inhibitors: plural of protease inhibitor; naturally-occurring and synthesised compounds that inhibit protease enzymes.

Proteases


Proteases are enzymes that split or break down proteins.

Protein


Protein is a long chain of amino acids, encoded in the genetic material, and translated from nucleotides into amino acids.

Proteins


Proteins: plural of protein; long chains of amino acids encoded in genes.

Proteolysis


Proteolysis is the process of peptide and protein breakdown.

Proteolytic


Proteolytic is an adjective pertaining to the breakdown of a protein or peptide. It is often used to describe a class of enzymes, proteolytic enzymes, that digest proteins and peptides.

Protozoa


Protozoa: plural of protozoan; eukaryotic unicellular organisms that can be free-living or parasitic. Malaraia and leishmaniasis are examples of diseases caused by protozoa.

Protozoan


Protozoan is a unicellular eukaryotic organism that can be free-living or parasitic. Protozoan is also an adjective pertaining to protozoa, eg, protozoan parasite.

Proximal


Proximal is an adjective pertaining to proximity, a location or distribution closest to a point of origin or attachment. In anatomy, proximal relates to the centre of the body, ie, A being proximal to B means A is closer to the centre of the body than B.

Prurigo


Prurigo is a group of disorders characterised by extremely itchy papules or nodules.

Pruritic


Pruritic is an adjective pertaining to pruritus, itch.

Pruritus


Pruritus is itch.

Pseudocyst


Pseudocyst is a firm lesion that contains fluid or semi-fluid material but, unlike a true cyst, it is not surrounded by a capsule or wall.

Pseudocysts


Pseudocysts: plural of pseudocyst; firm lesions that contains fluid or semi-fluid material. Unlike cysts, pseudocysts are not encapsulated.

Pseudoepitheliomatous


Pseudoepitheliomatous hyperplasia is a histological term for a harmless thickening of all layers of the epidermis that can resemble squamous cell carcinoma.

Pseudohypha


Pseudohypha is a branched filament produced by a yeast resembling a fungal hypha.

Pseudohyphae


Pseudohyphae: plural of pseudohypha; branched filaments produced by yeast resembling fungal hyphae.

Psoriasiform


Psoriasiform refers to a psoriasis-like skin condition.

Psychiatric


Psychiatric is an adjective pertaining to psychiatry, the study and care of mental conditions.

Psychocutaneous


Psychocutaneous is an adjective used to describe a disorder of the skin in which psychological factors play a major role. Psychocutaneous medicine is also called psychodermatology.

Psychodermatological


Psychodermatological is an adjective pertaining to a condition that affects both the skin and the mind. It has both physical and psychosocial components.

Psychodermatology


Psychodermatology is the study of skin conditions associated with, caused by, or triggered by mental conditions. Psychodermatology includes conditions that are primarily psychiatric in origin; others where the skin condition causes a secondary psychiatric issue such as depression or anxiety; skin conditions that flare with stress and therefore require treatment of both the stress and the skin; skin symptoms that are neurological in origin; and skin conditions that are treated with psychotropic medications.

Psychogenic


Psychogenic is an adjective pertaining to a psychiatric origin or cause.

Psychomotor


Psychomotor is an adjective pertaining to the interaction of neurological processes in motor (movement) skills. Psychomotor development is assessed in young children.

Psychosocial


Psychosocial is an adjective pertaining to the interaction of psychological and social events or impacts. In dermatology this may be used to describe the effect of a dermatosis such as psoriasis on mental health and social functioning.

Psychotropic


Psychotropic is an adjective meaning mind-altering. It is most commonly used to describe a class of drugs that affect mood, emotions, and other altered states of the mind.

Pterygium


Pterygium is a wing of extra tissue. In dermatology, pterygium typically describes an abnormal fold of skin connecting to nail in lichen planus and scleroderma. More commonly a pterygium affects the eye.

Ptosis


Ptosis is drooping of the upper eyelid.

Pulmonary


Pulmonary is an adjective pertaining to the lungs, eg, pulmonary artery, pulmonary tuberculosis.

Pulmonary embolism


Pulmonary embolism is the process of obstruction of an artery/arteries in the lung by a blood clot(s).

Pulpitis


Pulpitis is inflammation of the pulp - either the dental pulp or the fingertip pulp.

Punch biopsies


Punch biopsies: plural of punch biopsy; incisional biopsies of tissue obtained using a punch biopsy tool. It is also often used as a verb, eg, the dermatologist punch biopsies the rash.

Punch biopsy


Punch biopsy is an incisional biopsy of tissue obtained using a biopsy punch tool.

Punctate


Punctate is an adjective describing very small spots, dots or depressions.

Punctum


Punctum is a small tip or point.

Purpura


Purpura is both a singular and plural noun for the red, purple or brown, non-blancheable spots caused by bleeding into the skin. Purpura may be palpable or non-palpable, and range in size from 1 mm (petechiae) up to several cm across (ecchyoses).

Purpuras


Purpuras is the family of conditions characterised by purpuric lesions, non-blanchable red, purple or brown spots due to bleeding into the skin.

Purpuric


Purpuric is an adjective pertaining to purpura, non-blancheable red, purple or brown spots caused by bleeding into the skin.

Purulent


Purulent is an adjective describing the presence of pus.

Pus


Pus is thick yellow or green fluid consisting of neutrophil fragments, tissue debris, and serum. Although pus is usually considered indicative of a bacterial infection, in dermatology there are a number of non-infectious causes of sterile pus including psoriasis and Sweet syndrome.

Pustular


Pustular is an adjective pertaining to pus, a yellow-green fluid consisting of neutrophil fragments, tissue debris and serum. Pustular lesions may be the result of infection or inflammation such as psoriasis.

Pustule


Pustule is a small circumscribed epidermal lesion that contains pus. A pustule can be due to an infection but may also be sterile in an inflammatory condition.

Pustules


Pustules: plural of pustule; small circumscribed epidermal lesions that contain pus. Pustules can be due to infections or sterile in inflammatory conditions..

Pustulosis


Pustulosis is an inflammatory skin condition consisting mostly of pustules.

Pyknosis


Pyknosis is a histological term for the change seen in the nucleus of a cell undergoing apoptosis. It is characterised under the microscope as a shrinking and darkening of the nucleus.

Pyo-


Pyo- is a prefix pertaining to pus.

Pyoderma


Pyoderma means pus in the skin. Pyoderma is typically due to infection but can also be a sterile inflammatory disorder, eg, pyoderma gangrenosum.

Pyogenic


Pyogenic is an adjective pertaining to the production of pus. 'Pyogenic granuloma' however is not related to pus - see the webpage on this condition.

Q


Q switched


Q switched describes a specific mechanism of laser pulse formation producing a high-intensity beam in very short (nanosecond) pulses.

Q-switched


Q-switched describes a specific mechanism of laser pulse formation producing a high-intensity beam in very short (nanosecond) pulses.

Q-switched laser


Q-switched laser produces short (nanosecond) high-energy pulses. The technique involves modulating the Q factor of the laser resonator.

Q-switching


Q-switching is the technique of producing a high-intensity laser beam in very short (nanosecond) pulses.

Quadrant


Quadrant: is one quarter of an area.

Quadrants


Quadrants: plural of quadrant; more than one of the quarter sections.

Quotidian


Quotidian is an adjective meaning daily. Quotidian malaria is the form of malaria with daily fever spikes.

R


Radiation therapy


Radiation therapy is the treatment of disease using radiation including X-rays and electron beams.

Radiculopathy


Radiculopathy is a disease of a spinal nerve root.

Radiograph


Radiograph is an X-ray film.

Radiological


Radiological is an adjective pertaining to radiology, the medical specialty of imaging the living body, eg, radiological examination for a fracture.

Radiologist


Radiologist is a medical specialist who images the living body.

Radiotherapy


Radiotherapy is the treatment of disease using radiation including X-rays and electron beams.

Random


Random is an adjective or noun pertianing to chance or being unplanned.

Randomisation


Randomisation (American spelling randomization) is the process of making something random, determined by chance alone. In a comparative or placebo-controlled clinical trial, randomisation may involve the use of random numbers to determine which treatment arm a patient receives.

Randomised


Randomised (American spelling randomized) is an adjective pertaining to being random, distribution by chance. It is commonly used for clinical trials in which patients receive a particular treatment by chance.

Rash


Rash is an eruption of skin lesions which can be localised or widespread. Rash is also an adjective meaning impetuous or without thought.

Rashes


Rashes: plural of rash; skin eruptions which can be localised or widespread.

RASopathies


RASopathies: plural of RASopathy; genetic disorders caused by mutations in the RAS pathway.

RASopathy


RASopathy is a genetic disorder caused by a mutation in the RAS pathway.

Raynaud disease


Raynaud disease is the primary form of Raynaud phenomenon, meaning there is no apparent underlying or associated reason for the characteristic vasospastic response of fingers and toes to cold.

Raynaud phenomenon


Raynaud phenomenon is a vasospastic response to cold in which fingers or toes turn white and numb, and are bluish on rewarming before returning to normal. It may be primary (unknown cause) or secondary to connective tissue diseases.

Reagent


Reagent is a substance or mixture used in chemical analysis or other reactions.

Reagents


Reagents: plural of reagent; substances used in chemical reactions.

Recalcitrant


Recalcitrant is an adjective pertaining to being refractory or not complying, eg, a recalcitrant disease is refractory to or fails to respond to treatment.

Recall


Recall is a noun and verb related to remembering; a recollection or memory, or to remember. It is also used to mean summon back or return, as in a product recall.

Receptor


Receptor is a specialised molecule in or on a cell that binds to a specific agent that triggers an action. Examples of agents that have a specific cellular receptor include neurotransmitters, antigens, hormones, or other substances.

Rectal


Rectal is an adjective pertaining to the rectum, the end of the large bowel before the anus.

Rectum


Rectum is the muscular tube connecting the large bowel (colon) to the anus where faeces are accummulated prior to defaecation.

Recur


Recur is a verb meaning to keep coming back, repeatedly returning, to come back many times.

Recurrence


Recurrence is a return, something that has occurred again. In medicine a recurrence is the return of symptoms or signs despite treatment or apparent recovery from a condition.

Recurrent


Recurrent is an adjective pertaining to recurrence, a re-appearance, return or reoccurance, eg, a recurrent skin cancer has re-appeared after treatment.

Refractory


Refractory is an adjective pertaining to being resistant, stubborn, or unmanageable. A condition refractory to treatment fails to respond.

Regression


Regression is the process of returning to a previous state, a backward step, or relapse. In dermatology it is used to describe features seen clinically, with the dermatoscope or on histology, usually indicating destruction of a lesion.

Relapse


Relapse is a noun and verb pertaining to a falling back or to fall back. In medicine a relapse (or to relapse) is the recurrence of symptoms or signs after apparent recovery or improvement.

Relapses


Relapses: plural of relapse; multiple episodes of recurrent symptoms or signs after apparent recovery or improvement. Relapses is also used as a verb meaning deteriorates or recurs after improvement.

Remission


Remission is a reduction in or disappearance of symptoms or signs.

Remissions


Remissions: plural of remission; reduction in or disappearance of symptoms or signs.

Remit


Remit means to send back. In medicine it is an improvement in the severity of a condition, symptom, or sign, but not full recovery, for a period of time.

Renal


Renal is an adjective pertaining to the kidney.

Reoccur


Reoccur is a verb meaning to occur again, perhaps only once.

Repetition


Repetition is the process of repeating, doing again or happening again.

Repetitive


Repetitive is an adjective pertaining to repetition, repeated many times.

Resect


Resect is a verb meaning to cut out or excise.

Resection


Resection is the surgical removal of a piece of a tissue or an entire lesion or organ.

Rete


Rete is a network. In the skin, the rete pegs and ridges are the undulations at the dermoepidermal junction of interlacing downward projections of epidermis and upward projections of dermis.

Rete peg


Rete peg is a projection of epithelium into underlying connective tissue.

Rete pegs


Rete pegs: plural of rete peg; extensions of the epithelium that project down into the underlying connective tissue.

Rete ridge


Rete ridge is an upward projection of connective tissue between epithelial rete pegs.

Rete ridges


Rete ridges: plural of rete ridge; upward projections of dermis between the epidermal rete pegs.

Reticular


Reticular derives from the Latin for a small net, and is used as an adjective pertaining to a reticulum, a network.

Reticular dermis


Reticular dermis is the deep part of the dermis, composed of coarse elastic fibres and thick collagen bundles parallel to the skin surface.

Reticulate


Reticulate derives from the Latin to mean a small net, and is used as an adjective to mean covered by a net or network.

Reticulated


Reticulated derives from the Latin for a small net, and is an adjective used to describe being constructed like a net.

Retinoic acid


Retinoic acid is the acid form of vitamin A. In the body it is produced from retinol via retinaldehyde, and binds to nuclear retinoic acid receptors. There are three naturally occuring forms of retinoic acid: all-trans, 13-cis and 9-cis.

Retinoid


Retinoid is an adjective and noun pertaining to a molecule resembling vitamin A, eg, a retinoid drug. Common usage makes retinoid a noun used for a family of drugs related to vitamin A, eg, a retinoid (drug).

Retinoids


Retinoids: plural of retinoid (the noun); members of the retinoid family of drugs related to vitamin A.

Retinol


Retinol is vitamin A. It is the main form of vitamin A absorbed from the bowel, to be stored and transported around the body.

Retroauricular


Retroauricular is an adjective pertaining to the area behind the auricle (ear).

Rhabdomyolysis


Rhabdomyolysis is the potentially fatal destruction of muscle cells.

Rheumatic


Rheumatic is an adjective pertaining to inflammation of the joints, muscles, tendons, ligaments, or bones.

Rheumatism


Rheumatism is a general term for inflammation of joints or muscles.

Rheumatological


Rheumatological is an adjective pertaining to rheumatology, the study of diseases of the joints, muscles, tendons, and ligaments.

Rheumatologist


Rheumatologist is a medical specialist who manages conditions affecting the joints, tendons, ligaments, and muscles.

Rheumatology


Rheumatology is the study of diseases affecting the joints, muscles, ligaments, and tendons.

Rhinitis


Rhinitis is inflammation of the mucosal lining of the nose.

Rhytid


A rhytid is a wrinkle — a fine line in the skin.

Rhytide


Rhytide is a skin wrinkle caused by muscle contraction.

Rhytidectomy


Rhytidectomy is the surgical treatment of wrinkles.

Rhytides


Rhytides are wrinkles — fine lines in the skin.

Rhytids


Rhytids: plural of rhytid; superficial undesirable wrinkles in the skin, mostly due to ageing.

Ribonucleic acid


Ribonucleic acid (acronym RNA) is a molecule involved in the coding, replication and expression of genes. There are several different types of RNA in a cell including messenger RNA (mRNA), ribosomal RNA, and transfer RNA (tRNA). DNA is transcribed into mRNA by enzymes that read one strand of DNA converting the deoxyribose sugar into ribose and substituting the thymine base (T) for a uracil base (U). Ribosomal RNA and tRNA are involved in translating the mRNA code to amino acids and synthesising a protein. Some viruses use double-stranded or single-stranded RNA instead of DNA as their genetic material.

RNA


RNA is the acronym for ribonucleic acid, a molecule involved in the coding, replication and expression of genes. RNA is composed of the bases guanine, adenine, cytosine and uracil; a ribose sugar; phosphate group(s).

Rupioid


Rupioid is an adjective to resemble rupia; rupia comes from the Greek rhypos - filth. However rupioid is often used in dermatology to describe something as layered to resemble an oyster or limpet shell.

S


Saline


Saline is a weak salt solution of sodium chloride in water.

Saliva


Saliva is the clear watery fluid produced by salivary glands and secreted into the mouth to aid chewing and start digestion.

Salivary


Salivary is an adjective pertaining to saliva, the clear watery fluid secreted into the mouth to aid chewing and digestion.

Sarcoma


Sarcoma is a family of cancerous (malignant) growths (tumours) of non-epithelial (cells) including bone or soft tissues such as muscle or fat.

Sarcomas


Sarcomas: plural of sarcoma; cancerous (malignant) growths (tumours) of non-epithelial cells including bone or soft tissues such as muscle or fat.

Scale


Scale is used as a noun and verb. In the skin a scale is also called a squame, a flake of horny surface epidermis, such as on the surface of a lizard or fish. A scale is also used to measure as in a measuring device (eg, a kitchen scale) or a set of levels or numbers (eg, the Richter scale, or a skin severity scale). The verb to scale means to climb, ascend, overcome, (eg, to scale a mountain); to remove scales from the skin, (eg, to scale a fish).

Scales


Scales, plural of scale, surface keratin squames of scaly skin such as a lizard or snake; measuring devices, (eg, sets of kitchen scales, temperature scales). Scales is also a verb: to remove scales from a skin surface; to climb, ascend or overcome.

Scaling


Scaling is a noun, adjective, and verb. In the skin, scaling is the visible accumulation of keratin squames due to an increase in the dead cells on the skin surface (stratum corneum). As an adjective, scaling pertains to peeling. The verb scaling means climbing, ascending, overcoming.

Scaly


Scaly is an adjective pertaining to scale, a rough peeling surface, such as on the skin surface of a fish or snake.

Scar


Scar is a permanent mark due to healing with fibrosis.

Scarlatiniform


Scarlatiniform is an adjective meaning to resemble the rash of scarlet fever, typically a flat red rash.

Sclera


Sclera is the fibrous outer layer of the eyeball; white part of the eye.

Sclerae


Sclerae: plural of sclera; the outer layer of the eyes; the white part of the eyes.

Scleral


Scleral is an adjective pertaining to the sclera of the eye, the white fibrous layer of the eye.

Scleritis


Scleritis is inflammation of the sclera, the outer coat of the eyeball.

Sclerodactyly


Sclerodactyly is the thickening and tightness of the skin of the fingers or toes, which can result in spindle-shaped digits.

Scleroderma


Scleroderma literally means hardened skin, and occurs in several distinct diseases, including localised and systemic (generalised) disorders.

Sclerosis


Sclerosis is used clinically for hardened scar-like or indurated tissue. In histology, sclerosis describes increased collagen in the dermis with normal fibroblast numbers.

Sclerotic


Sclerotic is an adjective pertaining to sclerosis, hardened scar-like induration.

Scoliosis


Scoliosis is the sideways curvature of the spine.

SCORAD


SCORAD is a tool used for SCORing Atopic Dermatitis, and is used for assessment and monitoring.

Sebaceous


Sebaceous is an adjective pertaining to sebum, the oil (fat) produced by sebaceous glands in the skin.

Sebaceous gland


Sebaceous gland is the oil-producing gland in the skin.

Sebaceous glands


Sebaceous glands: plural of sebaceous gland; the oil-producing glands in the skin.

Sebocyte


Sebocyte is the cell in sebaceous glands that forms sebum by holocrine secretion.

Sebocytes


Sebocytes: plural of sebocyte; the cells in sebaceous glands that form sebum.

Seborrhoea


Seborrhoea (American spelling seborrhea) is increased sebum (the oil produced by seborrhoeic glands) on the skin surface resulting in a greasy feeling and shiny appearance.

Seborrhoeic


Seborrhoeic (American spelling seborrheic) is an adjective pertaining to seborrhoea or resembling seborrhoea. Use in dermatology does not always involve actual seborrhoea, including seborrhoeic area (where seborrhoeic glands are common), seborrhoeic dermatitis (typically involves seborrhoeic areas), and seborrhoeic keratosis (which can have a greasy appearance unrelated to seborrhoeic glands).

Sebum


Sebum is the oily substance produced by sebaceous glands by holocrine secretion.

Segmental


Segmental is an adjective pertaining to a segment, a part or section. A segmental distribution in dermatology describes involvement of one or more dermatomes or Blashko lines.

Seizure


Seizure pertains to the verb to seize, grip, grab. Seizure is used as a noun meaning an event involving grabbing or gripping, eg, a drug seizure by customs at the border. In medicine seizure means an event involving gripping or grabbing of the body as in an epileptic seizure or other form of focal excessive brain electrical activity.

Seizures


Seizures: plural of seizure; events grabbing or gripping, such as epileptic seizures.

Self antigen


A self antigen is part of the person's body that can induce an antibody response in some people. 

Self-antigen


Self-antigen is a normal protein or structure produced by a host cell targeted by an autoantibody.

Self-antigens


Self-antigens: plural of self-antigen; normal proteins or structures produced by host cells targeted by autoantibodies.

Self-limiting


Self-limiting: goes away without treatment.

Sensitisation


Sensitisation (American spelling sensitization) refers to the process of becoming sensitised (allergic) to an agent.

Sensorineural


Sensorineural is an adjective pertaining to the sensory nerves, eg, sensorineural deafness.

Sepsis


Sepsis refers to a state in which the patient is very unwell due to systemic bacterial infection or circulating toxins.

Septate


Septate is an adjective describing division into compartments by thick walls (septae)

Septic


Septic is an adjective pertaining to bacterial growth. A septic patient has a systemic bacterial infection and is very unwell with a high fever. A septic tank is an enclosed sewage system using bacterial activity to break down the contents.

Septicaemia


Septicaemia (American spelling septicemia) is a bacterial infection in the blood (blood poisoning).

Septicaemic


Septicaemic (American spelling septicemia) is an adjective pertaining to septicaemia, a serious bacterial blood infection.

Septum


Septum is a wall or partition that separates two parts, for example the nasal septum separates the two nostrils.

Sequela


Sequela is a negative after-effect or complication of a disease.

Sequelae


Sequelae: plural of sequela; negative after-effects or complications of disease.

Sera


Sera: plural of serum; the yellowish clear fraction of blood lacking blood cells.

Sero-purulent


Sero-purulent is an adjective pertaining to the combination of serum and pus.

Serological


Serological is an adjective relating to the serum, the fluid in the blood which excludes blood cells and clotting factors. It is typically used to describe blood tests using only serum such as detect antibodies and autoantibodies.

Serology


Serology refers to immune-related blood tests using serum, eg, viral serology to check response after immunisation.

Seronegative


Seronegative is an adjective decribing a negative reaction for a specific antibody in the serum.

Seropurulent


Seropurulent is an adjective pertaining to the combination of serum and pus.

Serous


Serous is an adjective pertaining to serum, eg, serous fluid contains only serum.

Serpentine


Serpentine is an adjective pertaining to a serpent (snake); serpentine describes having a curling or winding shape or movement like a snake. 

Serpiginous


Serpiginous is an adjective describing the shape of a snake or serpent.

Serum


Serum is the yellowish clear fluid lacking blood cells, derived from blood.

Sessile


Sessile is an adjective pertaining to being stuck-on. In dermatology, sessile is used to describe a lesion(s) stuck directly onto the skin surface without a stalk (peduncle).

Sex


Sex is determined by the appearance of the external genital anatomy at birth. Common usage also uses sex to mean sexual intercourse.

Shave biopsies


Shave biopsies: plural of shave biopsy; samples obtained by a cut (shave) made parallel to the surface of the surrounding tissue. Shave biopsies may remove all or part of lesions for diagnosis or cure. The term can also be used as a verb, eg, the dermatologist shave biopsies a skin papule.

Shave biopsy


Shave biopsy is a tissue sample obtained by a slice or cut made parallel to the surface of the surrounding skin. A shave biopsy may remove all or part of a lesion for diagnosis or cure.