Comparison of phenothrin shampoo and malathion lotion in the treatment of head louse infection.

Eighty patients (age range 4-10 years) with head lice infection were recruited to the study. Forty patients were treated with a single application of 0.2% w/v phenothrin liquid shampoo and 40 with 0.2% w/v malathion lotion. Inspection of the patients one week later revealed that no live lice remained in either group, but that two patients had viable eggs in the malathion lotion group. Re-inspection four weeks after application revealed that five patients of the phenothrin shampoo group and seven of the malathion lotion group had viable eggs. Live lice were not seen to be present in either treatment group. The results indicate that both products are effective in the treatment of head lice infection and that the phenothrin shampoo would be a useful addition to the insecticides currently employed.