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Last updated: January 2017
Scrapings taken from burrows may be examined under light microscopy to reveal mites, eggs, larvae or faeces collected from patient’s skin.
Observing typical lesions (characteristic silvery lines) in sites where mites have burrowed. Classic sites include wrists, finger web spaces, axillae, elbows, around breast/nipples in women. thighs, ankle, toe web spaces. Papules or nodules may be seen in the genital area.
Absorption of mite excrement into skin capillaries generate a hypersensitivity reaction which may take 4-6 weeks to develop
Main symptom is a generalised itch, with a classic pattern of pruritus at night, after a hot shower or bath.
If associated with exposure to an infected person, the index of suspicion should be high even in the context of non-specific symptoms.
Immunosuppressed patients (e.g. HIV patients) may present with Norwegian scabies – crusted lesions teeming with mites posing as a significant risk of transmission to others. This condition may not be pruritic.
Clinical appearance is typical but diagnostic confusion may occur with other itching dermatological conditions like eczema.
Secondary bacterial infection of skin lesions can occur following repeated scratching.
Permethrin 5% cream topical from neck downwards covering whole body, washed off after at least 12 hours overnight but not more than 24 hours (grade of recommendation A) (B2).
Note the following:
Ivermectin 200mcg/kg orally, repeated in 2 weeks (B3).
Norwegian scabies is usually treated with oral Ivermectin.
These patients may prove resistant to topical therapy. Review by a specialist may be necessary.
Permethrin is safe during pregnancy and breastfeeding.
The following points should be discussed:
Follow up is only indicated if symptoms have not resolved.
Appearance of new burrows at any stage post treatment is indicative of a need for further treatment.
In reinfections, symptoms of pruritis may recur before typical burrows have developed
Pruritus > 2 weeks after treatment may reflect treatment failure, reinfection or drug allergy to anti-scabetics.
For further information on the management and diagnosis of scabies, contact Adelaide Sexual Health Centre.
These guidelines are based on review of current literature, current national and international guidelines and recommendations, and expert opinion.
They are written primarily for use by Adelaide Sexual Health Centre staff and some flexibility is required in applying them to certain private practice situations.