Scabies Flashcards
What is scabies?
Scabies = very itchy rash caused by a parasitic mite that burrows in the skin surface
Who is at risk of scabies?
Most common in children, young adults, and elderly
Factors leading to the spread of scabies include:
=> Poverty and overcrowding
=> Institutional care i.e. care homes, hospitals, prisons
=> Refugee camps
=> Immunodeficiency
How is scabies spread?
Skin-to-skin contact with someone else with scabies
Sometimes sexually transmitted
Several scabies mites infest an affected host => after mating, the male mite dies.
Female scabies mite burrows into the outside layers of the skin => lays up to 3 eggs each day for her lifetime of 1-2 months.
The development from egg to adult scabies mite takes 10–14 days.
What are the clinical features of scabies?
Widespread intensely itchy, excoriated, eczematous rash triggered by a hypersensitivity response to mite allergens
Pruritus = worse at night + disturbs sleep
Small red papules, vesicles and sometimes pustules develop over the body
May be complicated by secondary bacterial infection
Fine linear or curved burrows a few millimetres long = diagnostic sign
How is scabies diagnosed?
Diagnosis sign = Fine linear or curved burrows a few millimetres long
Not always visible => dermascopy
Scabies can be confirmed under microscopy of potassium hydroxide treated skin scrapings from the tip of the burrow
*time consuming + treatment usually based on clinical findings
How is scabies treated?
- Topical 5% permethrin applied overnight
=> treat all skin neck down inc. genitalia, palms and soles
=> treat all close contacts
=> Reapply to hand if washed during treatment
=> Wash recently worn clothes
=> Re-apply permethrin after 1 week
- Malathion can be used if permethrin is unavailable
- Oral ivermectin 2 doses 2 weeks apart esp in residential homes
- Pruritus takes a few weeks to settle => antihistamines + cooling creams i.e. menthol 2%
