Malathion lotion is twice as effective as "bug busting" (wet combing with a fine toothed comb) for treating head lice, a study has found.
In a randomised controlled trial, pharmacist David Morgan and colleagues, from the department of public health, North Wales health authority, compared the use of a commercial wet combing kit used every three to four days for two weeks with two applications of 0.5 per cent malathion lotion, seven days apart.
The researchers screened 4,037 school children, aged three to 14 years, from two counties in Wales that had intermediate resistance to malathion. Participants were re-examined for head lice seven days after the end of treatment.
Of the 72 children analysed after treatment, the overall cure rate was 38 per cent (12 out of 32) for those who used the bug busting method, compared with 78 per cent (31 out of 40) for the malathion group. The researchers comment that the trial "suggests that policies advocating bug-busting as a first-line treatment for head lice infestation are inappropriate for the general population" (Lancet 2000;356:540).
Commenting on the study, Mrs Joanna Ibarra (programme co-ordinator, Community Hygiene Concern [CHC]), told The Journal on August 15 that the bug buster kit (available from CHC) used in the study was the 1996 version. The bug buster comb had since been improved and the new comb had a slightly longer angle on the tooth edge. Mrs Ibarra said that this increased the certainty of picking up first-stage lice which had just hatched. Commenting on the effectiveness figures for the two methods, she said that, since the study, resistance to malathion had increased whereas "you cannot become resistant to bug busting."
A three-year trial is currently being conducted by researchers at the London School of Hygiene and Tropical Medicine comparing the use of the current bug busting kit with insecticidal treatment with malathion and permethrin (Lyclear). Mr Nigel Hill (medical entomologist, London School of Hygiene and Tropical Medicine) told The Journal that this study involved a much larger area and data set than that in the Lancet study and was looking at single dose treatment and what the community would use and buy over the counter. He also commented that resistance could change rapidly and that care should be taken with interpreting trial data on head lice treatments.

Bug buster comb used to remove head lice