Links to pages about skin conditions that favour the arms.
- Erythema
- Red papules/pustules
- Erosions, crusting
- Dry scaly and itchy
- Dry scaly but not very itchy
- Skin coloured papules
- Pigmentary changes
Arms: erythema without surface change
Erythema is less pronounced in dark skin.
- Sun-exposed site
- Painful
- Consider phototoxic drugs
- Weals can arise on any site
- Spontaneous and inducible types
Arms: red papules/pustules
- Upper trunk
- Open and closed comedones
- Nodules + cysts if severe
- Crops of grouped itchy papules
- Central punctum
- May blister
- Inside wrists
- Firm, violaceous papules + white streaks
- Favours areas of earlier injury
- Also examine mouth, lower back, lower legs
Arms: erosions/crusting
- Dermatomal
- Painful
- Erythema may precede vesicles
- Culture/PCR: Herpes varicella zoster
- 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
Arms: dry/scaly and very itchy
May also blister, swell.
- Acute flares on any site
- Asymmetrical, odd-shaped patches/plaques
- Patch tests positive
- Patchy or diffuse
- Acute flares are erythematous
- Chronic eczema is lichenified
- Coin-shaped plaques
- Consider autoeczematisation from other site
Arms: dry and scaly with minimal itch
- Follicular papules
- Extensor upper arms
- Roughly symmetrical distribution
- Extensor elbows
- Well-circumscribed erythematous scaly plaques
- Variable itch
Arms: multiple skin coloured papules
- Extensor elbows, dorsum of hands and fingers
- Arranged in rings
Pigmentary changes
Pigmentation is more pronounced in dark skin.
- Preceding eczema, psoriasis, acne etc
- Distribution depends on cause
- Most often volar wrists
- White, smooth surface
See also pigmentary disorders