Nail diseases

This page outlines the terms used by dermatologists to describe diseases of the fingernails and toenails.

• Abnormalities of the nail plate surface
• Nail discolouration
• Abnormalities of the cuticle and nail fold
• Abnormalities of nail shape
• Loss of nails
• Lesions around nails

Abnormalities of the nail plate surface

Nail plate abnormalities are often due to inflammatory conditions affecting the matrix or nail bed. Specific diagnoses may be made from characteristic appearances.

Pitting Consider eczema, psoriasis (haphazard: upper image), alopecia areata (regular: lower image)
Transverse ridging Consider eczema (top image), paronychia (middle image), psoriasis, Beau's line (affects all nails, due to acute systemic illness stopping nail growth: lower image)
Onychorrhexis Longitudinal ridging. Consider aging (top image), lichen planus (middle image), psoriasis, fungal nail infection, Darier (bottom image) or a habit of picking
Longitudinal groove Median canaliform dystrophy due to Myxoid cyst (image) or wart
Median nail dystrophy Feathered longitudinal ridge
Onychogryphosis Thick hard curved nail plate in the shape of a ram's horn. due to aging (image), psoriasis or trauma
Onychauxis Thick nail due to psoriasis (top image), trauma or fungal nail infection (bottom image)
Angel-wing deformity Nail plate thinning due to lichen planus
Nail plate crumbling Typical of psoriasis (top image) & fungal nail infection (bottom image)
Onychoschizia Distal lamellar splitting/brittle nails due to water/detergent damage
Longitudinal splitting An extension of ridging seen in psoriasis, fungal nail infection (top image) or lichen planus (bottom image) Bottom image ©R Baran
Distal notching Consider Darier (image) and lichen planus
Trachyonychia Rough nails. If all nails affected, known as Twenty Nail Dystrophy, probably due to lichen planus
Erosion Consider trauma or malignant tumour e.g. SCC or melanoma (image)
Acrylic nails Decorative cosmetic

Nail discolouration

Distinguish a discoloured nail bed from a discoloured nail plate.

Yellow nail syndrome Yellow or green nails due to lymphatic obstruction in cardiopulmonary disease
Green nails Pseudomonas/candida infection
Yellow nails Due to fungal nail infection
Lateral yellow streak Due to dermatophyte onychomycosis
Yellow nails Due to psoriasis
Oil-drop or salmon patch Due to psoriasis: orange or brown streak proximal to onycholysis
Brown nails Consider staining (nicotine, potassium permanganate, nail varnish) and chemotherapy. Illustrated are staing from podophyllin (top image) and streaks due to oral hydroxyurea (bottom image).
Vitiligo White nails and adjacent skin
Leukonychia White nails. Consider hypoalbuminaemia or chronic renal failure. May be familial. Transverse leukonychia, or multiple parallel white lines, are thought to be due to manicuring but may also arise in association with Beau's lines.
White streaks Traumatic e.g. manicuring
Onycholysis White or yellow distal nail, lifted off. Consider idiopathic causes (top image), trauma, psoriasis (second image), thyrotoxicosis, irritant & allergic contact dermatitis, fungal nail infection (candida: third image), drug photosensitivity (especially tetracycline: bottom image; and psoralens)
White spotting Due to superficial white onychomycosis
Half-and-half nails Seen in renal failure. White proximal nail, brown distal nail
Terry's nails Seen in liver cirrhosis. White proximal nail, reddened distal nail
Mee's lines Partial leukonychia due to arsenic intoxication or systemic disease
Muehrcke's lines Double band of leukonychia in renal disease
Red lunula
Red & white streaks Seen in Darier disease
Red tender area Consider glomus tumour Image ©R Baran
Blue nail Consider drugs (all nails affected), in this case minocycline
Red/purple streak Splinter haemorrhage
Purple/black nail Haematoma (blood clot)
Black nail Pseudomonas infection
Brown/black linear streak Benign melanocytic naevus.
Multiple brown linear streaks Also called longitudinal melanonychia. May be of racial origin or Laugier-Hunziker Syndrome. Rarely due to drug (azidothymidine, tetracycline), endocrine disorders or Peutz-Jeghers syndrome.
Expanding variable colour/shaped streak Consider melanoma Bottom image ©R Baran

Abnormalities of the cuticle and nail fold

The cuticle is an area of keratin joining the skin of the posterior nail fold to the nail plate. Loss of cuticle reuslts in paronychia.

Ragged cuticles Connective tissue disease
Hang nail Trauma (biting)
Nail fold telangiectases Connective tissue disease e.g. lupus erythematosus
Vasculitis Distal digital infarcts
Subungual hyperkeratosis Scaling under hyponychium. Typical of psoriasis (top image) & onychomycosis but also arises in crusted scabies (bottom image)
Pterygium Due to scarring in nail matrix. Characteristic of lichen planus (image) but may occur in Stevens-Johnson syndrome and from trauma
Acute paronychia Staphylococcus aureus
Acute paronychia Herpes simplex
Chronic paronychia Candida albicans or pseudomonas
Acrodermatitis continua of Hallopeau A form of severe psoriasis
Retronychia Embedding of the nail into the nail fold and subsequent inflammation.

Abnormalities of nail shape

Enlarged Osteoid osteoma (bone tumour) ©R Baran
Long Uncut
Brachyonychia Short
Over-curvature Resorption of distal phalanx
Clubbing Due to hypertrophic osteoarthropathy (image) or thryoid disease (acropachy)
Koilonychia Thin spoon-shaped nail associated with iron deficiency anaemia & acitretin treatment ©R Suhonen
Pachyonychia Wedge-shaped nails
Pincer nail Sometimes familial or associated with psoriasis
Onychocryptosis In-growing nail with granuloma formation. Aggravated by retinoids such as isotretinoin or acitretin

Loss of nails

Without scarring Usually traumatic eg nail biting
Scarring Due to tumour (upper image) or erosive lichen planus (bottom image) Bottom image © R Baran
Onychomadesis Nail shedding may arise in severe or bullous lichen planus (image) or acute and severe systemic illness

Lesions around nails

Common skin lesions around nails include:

Viral warts
Melanocytic naevus
Melanoma
Squamous cell carcinoma or keratoacanthoma (image) ©R Baran
Corn
Subungual fibroma
Subungual exostosis
Myxoid cyst
Pyogenic granuloma