- Scabies infection produces intense pruritus, especially on the trunk and limbs, and at night.
- There are usually limited visible signs of the infestation but burrows may sometimes be observed on the wrists, finger web spaces or the sides and soles of the feet.
- Complaints of intense pruritus should raise a suspicion of scabies, especially if there is a family report of similar symptoms.
- Treatment of both the infested person and their close physical contacts should begin immediately, regardless of whether they are symptomatic. Finger and toe nails should be cut short to prevent scratching and carriage of mites and eggs.
- Linen (Sheets, pillowcases, towels) and clothing should also be washed regularly and not shared during infestation.
- Permethrin appears to be the most effective topical scabicide and is considered the safest under 6 months. Malathion lotion may also be considered. Permethrin 5% lotion (A-Scabies®) and malathion 0.5% liquid (A-Lices®, Derbac-M®) are both available fully funded in New Zealand.
- Success or failure of therapy for scabies infestation depends much more on correct application of the topical preparation and treating all household contacts, than on which scabicide to use.
- Topical gamma benzene hexachloride (Lindane or Benhex) has been used in the past but is now not recommended due to toxicity concerns.
- Scabicides should be applied to the entire body, from below the chin and ears, concentrating on the areas between the toes and fingers, genitals and under the nails (use a soft brush if required). Treatment should be applied to the face (avoid eye area) and scalp in children aged under two years, people who are immunocompromised and elderly people. Treatment should be reapplied to areas that are washed within the application time e.g. after hand washing. The treatment (both lotion and cream formulae) needs to be left on the body overnight and washed off the following morning. Clean linen and clothes should then be used.
- All personal linen (sheets, pillow cases,towels,blankets in direct contact with skin) and clothing worn next to the skin (underwear, T-shirts, socks, pants) should be laundered in a hot wash cycle.
- If hot water is not available, place all linen and clothing into plastic bags and store it away from the family for five to seven days. The mite does not survive beyond four days without skin contact.
- Children may return to day care or school the day after treatment is completed.
- Repeat application of the treatment is often required in 10-14 days. Linen(Sheets,pillowcases,towels) and clothing should also be washed regularly.
Symptoms of itch can continue for several weeks after treatment. The most frequent complication of treatment with topical scabicides is post-scabies eczema (generalised eczematous dermatitis). Because of the irritant effects of the various formulations, xerosis (dry skin) might increase and worsen eczema, which could be mistaken for drug failure or re-infestation. Therefore, rehydration of the skin using emollients and anti-inflammatory therapy with topical steroids can be useful.
Treatment Resistant Scabies:
- Most treatment failures are due to inadequate treatment or reinfection or persistent itch.
- Ivermectin 3mgs can be used when prior treatment has failed.
- It is not funded and is moderately expensive.
- Single dose required at 200microgram/kg.
- Safety in children under 15kg not established although generally well tolerated.
- Consider administration second dose within 2 weeks after initial dose if new specific lesions or heavily infected.
Last updated : Thursday, May 18, 2017
Next review date : Friday, May 18,2018
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