Comparison of wet combing with malathion for treatment of head lice in theUK: a pragmatic randomised controlled trial

Background Concern about the effectiveness and toxicity of insecticide loti ons has led to promotion of mechanical methods to remove head lice. We comp ared the effectiveness of "bug-busting" (wet combing with a fine-toothed co mb) and malathion lotion. Methods We screened 4037 schoolchildren in two counties in Wales. UK (inter mediate resistance to malathion). Of 167 found to have head lice, 81 (aged 3-14 years) were eligible to participate in a randomised controlled trial t hat compared mechanical removal of lice by a commercial kit every 3-4 days for 2 weeks with two applications of 0.5% malathion lotion 7 days apart; pa rents carried out both treatments. The outcome measure was the presence of live lice 7 days after the end of treatment. Analyses were by intention to treat. Findings 74 children completed the study and 72 were included in the analys is. The cure rate was 38% (12 of 32) for bug-busting and 78% (31 of 40) for malathion. Children assigned bug-busting were 2.8 (95% CI 1.5-5.2) times m ore likely than those assigned malathion to have lice at the end of treatme nt (p=0.0006). Interpretation Malathion lotion was twice as effective as bug busting, even in an area with intermediate resistance. Policies advocating bug-busting a s first-line treatment for head lice in the general population are inapprop riate. Assessment of the outcome of treatment 1-2 weeks after completion is essential for successful management. Only about 50% of participants compli ed fully with treatment, so future trials should be pragmatic in design, av oid false incentives, and study representative samples of children.