11.20 Scabies
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agk's Library of Common Simple Emergencies

Presentation
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Patients may rush to the emergency department 
shortly after having gone to bed, unable to sleep 
because of severe itching. Papules and vesicles 
(marking deposition of eggs) along thread-like 
tracks (mite burrows) are chiefly found in the 
interdigital web spaces as well as on the volar 
aspects of the wrists, antecubital fossa, 
olecranon area, nipples, umbilicus, lower 
abdomen, genitalia and gluteal cleft. Secondary 
bacterial infection is often present.

What to do:
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- Attempt identification of the mite by placing 
    mineral oil over the papule or vesicle at the 
    proximal end of a track and scraping it with 
    a #15 scalpel blade onto a microscope slide. 
    Examine it under low magnification for either 
    the mite or its oval eggs or fecal 
    concretions.
- If the clinical picture is convincing, 
    treatment should be instituted without the 
    help of microscopic examination, or even in 
    the face of negative scrapings.
- Treat with lindane (Kwell) lotion to the entire 
    body from the neck down. Concentrate on the 
    affected areas. The patient should apply this 
    prescription medication and leave it on for 
    24 hours before washing it off (60-120ml is 
    required for the average adult). It may be 
    necessary to repeat this treatment after 1 
    week, but not sooner. Tell the patient that 
    the itching will not go away at once, but 
    that this does not mean the Kwell was 
    ineffective. Dead mites and eggs continue to 
    itch as they are absorbed by the body. An 
    antipruritic agent such as hydroxyzine 
    (Atarax) 25mg q6h can be prescribed for 
    comfort.
- Alternatively, treat with a similar application 
    of crotamiton (Eurax) lotion or cream to the 
    body after bathing, repeated after 24 hours. 
    This treatment can also reduce itching.
- Clothing, bedding, and towels should be washed 
    with hot water or dry cleaned to prevent 
    reinfection.

What not to do:
---------------

- Do not use Kwell on infants, young children, or 
    pregnant women. Up to 10% of this pesticide 
    may be absorbed percutaneously, producing 
    seizures or CNS toxicity, and therefore an 
    alternative treatment should be sought. 
    Crotamiton (Eurax) cream applied twice during 
    a 48 hr period will be effective and also 
    acts as an antipruritic agent.

Discussion
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Scabies is caused by infestation with the mite 
Sarcoptes scabiei. The female mite, which is just 
visible to the human eye, excavates a burrow in 
the stratum corneum and travels about 2mm a day 
for about 1-2 months before dying. During this 
time she lays eggs which reach maturity in about 
3 weeks. Scabies is transmitted principally 
through close personal contact, but may be 
transmitted through clothing, linens, or towels. 
Severe pruritis is probably caused by an acquired 
sensitivity to the organism and is first noted 
2-4 weeks after primary infestation. Sometimes 
nonspecific, pruritic, generalized maculopapular 
excoriated rash, turns out, after a therapeutic 
trial of Kwell, to have heen an atypical case of 
scabies.

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 from Buttaravoli & Stair: COMMON SIMPLE EMERGENCIES
 Longwood Information LLC 4822 Quebec St NW Wash DC
 1.202.237.0971 fax 1.202.244.8393 electra@clark.net
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