Clinical Question: In children with head lice, is fine-tooth combing of the hair as effective as treatment with an insecticide?
Setting: Outpatient (primary care)
Study Design: Randomized controlled trial (single-blinded)
Synopsis: Resistance to pediculicides can be high in some areas, often topping 80 percent. This study evaluated the effectiveness of using a specific fine-tooth comb (Bug Buster, not available in the United States) on conditioned hair compared with two pediculicides in 133 children, two to 15 years of age, with head lice. The investigators recruited children from the offices of family physicians and via advertisements in pharmacies and schools. The children were randomized, with allocation unconcealed, to be treated using combing or the pediculicides malathion 0.5 percent or permethrin (Nix), depending on the availability in local pharmacies. Combing was done on wet, conditioned hair to remove lice and nits, and was performed every three days for a total of four combings. The pediculicides were used once, following the directions on the label, but are more commonly used twice, one week apart. Children were examined for the presence of lice five days after treatment with a pediculicide and 15 days after the start of the combing regimen by a study nurse unaware of their treatment, with failure determined as the presence of one or more live lice. Using intention-to-treat analysis, 14 percent of the children were lice-free at follow-up after a single treatment with the pediculicides, whereas 52 percent were lice-free with the combing regimen (number needed to treat = 2.6; 95% confidence interval, 1.2 to 7.1). Cure rates might be affected by the type of comb; rates in a previous study were lower when an earlier version of the comb was used (Roberts RJ, et al. Comparison of wet combing with malathion for treatment of head lice in the UK: a pragmatic randomised controlled trial. Lancet 2000;356:540–4).
Bottom Line: Approximately one half of children using a specific lice comb every three days for nine days will be lice free at a two-week follow-up. This rate was higher than that with either of two commonly used pediculicides, although they were only used once instead of twice, as commonly recommended. Combing is not technically difficult as long as conditioner has been used on the hair, although it is a less desirable option to the parent. Although this staggered assessment of outcomes might make sense given the risk of reinfestation, this study would have been much stronger if both groups had been evaluated after 15 days and if the children in the pediculicide group had received two treatments. (Level of Evidence: 1b–)