Safety and efficacy of a non-pesticide-based head lice treatment: Results of a randomised comparative trial in children

Abstract

Increasing resistance to pesticide-based head lice treatments has resulted in the need for alternative products to treat head lice infestations, but there are few clinical studies that have adequately tested these products. This multicentre, randomised, assessor-blind, parallel-group phase IV trial compared the safety and efficacy of a non-pesticide-based head lice shampoo with malathion foam in children. This trial used strict entry criteria, standardised treatment and assessment regimes, sibling control and a primary efficacy end-point defined as the absence of live head lice 21 days after initiating treatment. Repeat insult patch tests were performed to further assess the safety of the non-pesticide-based shampoo. In vitro tests were used to assess its ovicidal and pediculicidal efficacy. A total of 216 children were enrolled, of whom 172 were per-protocol. The non-pesticide-based shampoo was significantly more effective than malathion foam for the intent-to-treat population (62.3 vs 40.4% louse-free, unadjusted P = 0.002; adjusted P = 0.003), as well as for the per-protocol population (67.8 vs 43.0% louse-free, unadjusted P = 0.001; adjusted P = 0.004). Adverse events were limited to itching or stinging. Patch testing with the non-pesticide-based shampoo resulted in no adverse reactions. In vitro tests using body lice demonstrated that the non-pesticide-based shampoo is ovicidal and pediculicidal. The non-pesticide-based shampoo is significantly more effective in eliminating head lice than malathion foam in children, while being associated with a low incidence of mild, transient adverse events.