Skin problems on the trunk

Links to pages about skin conditions that favour the trunk.

• Erythema
• Red papules/pustules
• Erosions, crusting
• Dry scaly and itchy
• Dry scaly but not very itchy
• Skin coloured papules
• Pigmentary changes

Trunk: erythema without surface change

Erythema is less pronounced in dark skin.

Flushing

• Intermittent redness eg when hot, embarrassed or with certain foods
• Often lifelong tendency
• Systemically well
• May precede/accompany rosacea

Sunburn

• Sun-exposed site
• Painful
• Consider phototoxic drugs

Urticaria

• Weals can arise on any site
• Spontaneous and inducible types

Trunk: red papules/pustules

Acne vulgaris

• Upper trunk
• Open and closed comedones
• Nodules + cysts if severe

Hot tub folliculitis

• Bathing costume distribution
• Exposed to hot tub
• Papulopustules
• Rarely, fever

Lichen planus

• Lower back
• Firm, violaceous papules + white streaks
• Favours areas of earlier injury
• Also examine mouth, distal limbs

Malassezia follicultiis

• Upper trunk
• Monomorphous superficial papulopustules

Miliaria

• Mid trunk
• Acute non-follicular papulopustules
• Follows heat/sweating

Morbilliform drug eruption

• Entire trunk spreading to limbs
• Commenced new drug within 10 days
• Monomorphic macules and papules
• Variable itch

Trunk: erosions/crusting

Herpes zoster

• Dermatomal
• Painful
• Erythema may precede vesicles
• Culture/PCR: Herpes varicella zoster

Impetigo

• Irregular enlarging plaque
• Honey-coloured crusts
• Culture: Staphylococcus aureus +/- Streptococcus pyogenes

Scabies rash

• Burrows between fingers, wrists
• Nodules in axillae, groin
• Intense itch, especially at night
• Dermatoscopy of burrow reveals mite

Transient acantholytic dermatosis / Grover disease

• Acute or chronic
• Itchy or asymptomatic
• Elderly males
• Crusted papules

Varicella/chickenpox

• Febrile illness
• Also involves face, oral mucosa
• Monomorphic eruption
• Culture/PCR: Herpes varicella zoster

Trunk: dry/scaly + very itchy

May also blister, swell.

Allergic contact dermatitis

• Acute flares on any site
• Asymmetrical, odd-shaped patches/plaques
• Patch tests positive

Atopic dermatitis

• Patchy or diffuse
• Acute flares are erythematous
• Chronic eczema is lichenified

Nummular dermatitis

• Coin-shaped plaques
• Consider autoeczematisation from other site

Secondary syphilis

• Rash involves palms, soles
• Positive syphilis serology

Trunk: dry and scaly with minimal itch

Annular erythema

• Slowly enlarging rings
• Scale just inside periphery

Pityriasis rosea

• Distribution along Langers lines (fir tree pattern)
• Larger herald patch appears several days before others
• Oval shaped plaques with scale just inside periphery
• Variable itch

Pityriasis versicolor

• Mid-upper back and mid chest
• Pale, pink or brown macules, patches
• Diffuse bran-like scale
• Mycology microscopy negative, culture positive

Psoriasis

• Roughly symmetrical distribution
• Well-circumscribed erythematous scaly plaques
• Variable itch

Seborrhoeic dermatitis

• Mid-upper back and mid chest
• Erythema, flaking
• Skin feels rough on palpation
• Often, follicular prominence

Subacute cutaneous lupus erythematosus

• Upper trunk
• Thin erythematous plaques
• Peripheral scale
• Check CBC, ANA, ENA
• Biopsy confirmatory

Tinea corporis

• Asymmetrical annular or discoid shaped plaques
• Peripheral scale
• Mycology microscopy + culture positive

Trunk: multiple skin coloured papules

Comedonal acne

• Open and closed comedones
• Folliculocentric

Granuloma annulare

• Arranged in rings

Steatocystoma multiplex

• Genodermatosis
• Superficial pseudocysts

Pigmentary changes

Pigmentation is more pronounced in dark skin.

Postinflammatory pigmentation

• Preceding eczema, psoriasis, acne etc
• Distribution depends on cause

See also pigmentary disorders