Scabies
Background
- Sacoptes scabiae var. hominis.
- Female burrows through skin (finger webs, elbows, wrists).
- 2-3 eggs per day in burrow (for up to 2 months!).
- Larvae emerge 3 days later.
- Live cycle complete in 10-14 days. Mites live circa 30 days.
- Incubation period (1st) 2-4 weeks - allergic reaction develops to mite faeces.
Clinical
- Itch , rash, papules.
- Scratching and eventual lichenification.
- Hands,(finger webs), wrists, elbows, male genitalia, buttocks, axillae.
- ( In contrast allergic Rxn usually midriff, inside thighs axillae, legs)
Diagnosis
- Hx often very persuasive!
- ID burrow with mite at one end (good light, magnifying glass).
- Crusted ("Norwegian") scabies found in elderly, alcoholics, Down's syndrome, AIDS, immunosuppressed.
Treatment
- Oral antihistamines (itch) if required.
- Permethrin (or malathion).
- Household contacts treated AT SAME TIME.
- Two treatments, one week apart.
- Asymptomatic contacts (> 10 minutes contact) need one treatment
Notes
- Anybody else at home got itch?
- 80% of males have genital involvement.
- No head / neck involvement as too cold.
- Don’t look for burrows treat on Hx alone. GP to refer dermatology if fails.
Links
Content by Dr Íomhar O' Sullivan 14/03/2009. Last review Dr ÍOS 4/12/18.