SCABIES

Contagious skin disease associated with severe itch

Cause

  • A parasitic mite, Sarcopterus scabiei hominis
  • Transmitted by direct skin contact with infected person

Clinical features

  • Intense itching, especially at night
  • Wheals, papules, vesicles, and thread-like burrows
    • Common in flexural areas, i.e. wrists and inter-digital creases, axillae, nipples, buttocks, and genitalia
  • Scratching spreads mites to other areas leading to widespread, intensely pruritic eruption
  • Secondary infection is common

Differential diagnosis

  • Papular urticaria, atopic or seborrhoeic dermatitis
  • Drug eruptions
  • Onchocerciasis

Investigations

  • Microscopic identification of mites, their eggs or faeces obtained from the vesicles or mite burrows

MANAGEMENT

General measures

  • Close contacts and all family members in the household should be treated
  • Wash and iron all linen which has touched the infected skin

Medicine treatment

  • Wash (scrub) the body well
  • Apply benzyl benzoate lotion 25% to the whole body from the scalp to the soles of the feet but
    taking care to avoid contact with the eyes. Leave on for 24 hours, rinse and reapply. Repeat 2 times
    except in pregnant women
  • Give an antihistamine to relieve itching: tablet chorpheniramine 4 mg every 8 hours for 3 days
    Child: 1- 2 mg per dose

If treatment ineffective or unsuitable

  • Ivermectin 200 micrograms single dose (avoid in pregnancy, and in children <15 kg)
  • For complete eradication of mites, repeat the dose after 7 days

If secondary infection is present

  • Give an antibiotic as in Boils

Prevention

  • Personal hygiene (washing clothes and regular bathing)
  • Avoid close contact with infected people