Background
Human scabies is a debilitating skin disease caused by Sarcoptes scabei, known by several names such as "itch mite." At any given time, the worldwide burden of disease is about 300,000,000 people. It is an arthropod infestation primarily affecting impoverished populations. Ordinary scabies is treated with permethrin-based creams and shampoos while crusted "Norwegian" scabies is often treated with a combination of permethrin (5%) and oral ivermectin 200 µ/kg. Antibiotics are used when there is a secondary bacterial skin infection usually resulting from the excoriation of scratching and compromise of the integument by the mites themselves.
Methods
Strong and Johnstone[1] recently updated the Cochrane Database on this topic last reviewed by this group in 2000. The objective was to compare extant literature on topical and oral interventions. The authors searched the Cochrane Infectious Diseases Group Specialized Register, MEDLINE, EMBASE, INMED and others to find randomized, controlled trials of drug treatments for scabies. Additionally, they searched reference materials from the retrieved studies and ongoing, registered trials.
Results
The authors found twenty trials with a total of 2392 participants. The most commonly studied compounds were the pyrethrins, ivermectin, lindane, sulfur and benzyl benzoate. No serious adverse effects were reported in any study of topical or oral agents used to treat ordinary scabies or crusted scabies.
Conclusions
The authors concluded that topical permethrin and oral ivermectin are the most effective treatments for scabies.
Relevance to Emergency Medicine
Most emergency physicians are familiar with topical treatments for scabies such as those containing permethrin (e.g. Elimite). Oral agents are not commonly used in the United States either because medications such as ivermectin aren’t on formulary or because physicians are not familiar with this strategy of scabies management. Many compounds with proven or suspected acaricidal activity have been tried since antiquity. In the 20th century and in this century, ivermectin has been used safely in millions of people to eradicate diseases such as river blindness caused by Onchocerca volvulus and to treat common parasitic diseases such as filiariasis. Ivermectin (200 µ/kg) has been effectively used in single doses and in doses separated by 10 days to control scabies.[2] Further studies need to be performed in institutional and community settings, but physicians should consider this cost effective treatment and clinically effective treatment in patients who are allergic to permethrin formulations or in those who are not likely to follow through on their treatment plans if given a prescription for topical formulations. Ivermectin typically comes in 6 or 12 mg scored tablets.
AccessMedicine from McGraw-Hill © 2010 The McGraw-Hill Companies
All rights reserved. From Tintinalli's Emergency Medicine
Cite this: Interventions For Treating Scabies -- Oral Ivermectin - Medscape - Dec 09, 2010.
