Hot air is an effective treatment for head lice

Article Outline

• Goates BM, Atkin JS, Wilding KG, Birch KG, Cottam MR, Bush SE, et al. An effective nonchemical treatment for head lice: a lot of hot air. Pediatrics 2006;118:1962-70
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Goates BM, Atkin JS, Wilding KG, Birch KG, Cottam MR, Bush SE, et al. An effective nonchemical treatment for head lice: a lot of hot air. Pediatrics 2006;118:1962-70 

Question Among children with head lice, how effective is hot air at eradicating the lice and their eggs?

Design Observational trial.

Setting University of Utah.

Participants 169 elementary school children (>6 years of age) with head lice infestation.

Intervention Six different hot air treatment methods were tested. Follow-up inspections were performed on 11 subjects to evaluate whether the most successful method resulted in cure of the head louse infestation.

Outcomes Egg and louse mortality.

Results All 6 methods resulted in high egg mortality (>88%), but they showed more-variable success in killing hatched lice. The most successful method, which used a custom-built machine called the LouseBuster™, resulted in nearly 100% mortality of eggs and 80% mortality of hatched lice. The LouseBuster™ was effective in killing lice and their eggs when operated at a comfortable temperature, slightly cooler than a standard blow-dryer. Ten of 11 subjects were cured of head lice when examined 1 week after treatment with the LouseBuster™. There were no adverse effects of treatment.

Conclusions One 30-minute application of hot air is an effective, safe treatment for head lice, and one to which lice are unlikely to evolve resistance.

Comment Head lice is a common problem in children that is frequently seen in any pediatric practice and school. Head lice can be effectively treated with chemical shampoos such as pyrethroids or lindane, but developing resistance makes these methods less effective. Based on observations made more than 60 years ago that hot air can effectively kill body lice, the investigators have tested six different methods of using hot air to eradicate head lice and their eggs. They used different techniques with a bonnet-style hairdryer, a handheld blow-dryer, a wall-mounted dryer, and a custom-built high-volume, hot-air blower named the LouseBuster™ (developed by study authors). A protocol was developed to standardize removal of head lice and eggs before and after the treatments on different sides of the head, and statistical power (>0.80 to detect a medium effect size [d = 0.50]) was calculated for each method. Each method effectively killed lice eggs (all >88%), but the effect on head lice (range, 10%-80%) and the reported discomfort (range, 11%-50%) varied widely. The LouseBuster™ with a specially designed hand-piece was the most effective (80% louse mortality, 98% egg mortality) and well-tolerated (11% reported discomfort) method. There are some caveats to these results. First, the study was small, and the participants were not randomized. In addition, no direct comparison was made to standard chemical shampoos, which have been previously reported to cause 60% mortality of eggs in situ. Thus, it is difficult to determine if this new method offers any advantage, although the egg mortality is higher in the present study. Although the LouseBuster™ seems to be very effective and could be used by trained personnel in a variety of clinical settings (office, school, or day care), the 30-minute treatment time makes this method less practical, and potentially costly. Further randomized studies with shorter treatment times and comparisons with standard therapies will be useful as we decide whether this innovative treatment should be implemented more widely.