Interventions for treating scabies.

BACKGROUND: Scabies is a common public health problem with an estimated global prevalence of 300 million. Infestation can cause considerable discomfort and intense itching. Severe adverse effects have been reported for some drugs used to treat scabies.
OBJECTIVES: The objective of this review is to assess the effects and toxicity of topical and systemic drug treatment for scabies. SEARCH STRATEGY: We searched the Cochrane Infectious Diseases Group trials register, the Cochrane Controlled Trials Register, MEDLINE, EMBASE, military records, traditional medicine databases. We also contacted international specialist centres and drug manufacturers. SELECTION CRITERIA: Randomised controlled trials of any drug treatment for scabies. Tolerability and toxicity were sought in any study of humans taking any drug treatments for scabies. DATA COLLECTION AND ANALYSIS: Two reviewers assessed trial quality and extracted data. MAIN
RESULTS: Thirteen trials were included (nine compared drug treatments, two compared treatment regimens, one compared the drug vehicle, and one was a community intervention). In one small trial, ivermectin was associated with a significant higher clinical cure rate at seven days when compared with placebo. Permethrin appeared to be more effective than crotamiton for clinical and parasitic cure rates. Permethrin appeared to be better than lindane for clinical cure rates in two small trials, but had no advantage in the largest trial (test for heterogeneity P < 0.001). Permethrin also appeared more effective in reducing itch persistence than lindane. There appeared to be no difference in clinical cure rates between crotamiton and lindane or benzyl benzoate and sulphur. Two trials assessed: the effectiveness of oral versus topical treatment (ivermectin versus benzyl benzoate and ivermectin ); single trial assessed treatment vehicle (pork fat versus cold cream); and mass community treatment (ivermectin), but all were too small to demonstrate an effect. No randomised trials of malathion were identified. Serious adverse drug reactions (including death and convulsions), most notably to lindane, permethrin and ivermectin, have been reported elsewhere. REVIEWER'S
CONCLUSIONS: The evidence that permethrin is more effective than lindane is inconsistent. Lindane, permethrin, and ivermectin appear to be associated with rare but serious drug reactions although this is not derived from trial data. More research is needed on the safety and effectiveness of ivermectin and malathion compared to permethrin, on community management, and on different regimens and vehicles for topical treatment.