HealthDay News — A single 10-minute, at-home treatment with topical ivermectin lotion (Sklice) eliminates head lice infestations in nearly all patients by the next day without nit combing, results from two phase 3 clinical trials show.

A significantly higher proportion of patients treated with 0.5% ivermectin lotion were louse-free compared with patients treated with an inactive comparator at 1 day (94.9% versus 31.3%), 1 week (85.2% versus 20.8%) and 2 weeks (73.8% versus 17.6%) after treatment, David M. Pariser, MD, of the Eastern Virginia Medical School in Norfolk, and colleagues reported in the New England Journal of Medicine.

The difference were statistically significant at each time point (P<0.001 for all) and rates of adverse events were similar between the two treatment groups. The study involved a total of 765 patients aged 6 months or older with head lice.

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“The results of the two studies reported here indicate that ivermectin is a treatment option when permethrin or pyrethrins have failed or when there is a desire to reduce the need for nit combing and increase the probability of success with a single application,” the researchers wrote.

In an accompanying editorial, Olivier Chosidow, MD, PhD, of the French National Institute of Health and Medical Research (INSERM) Clinical Investigation Center in Creteil, and Bruno Giraudeau, PhD, of INSERM in Paris, emphasized that invermectin lotion should not be used as a first-line treatment option due to concerns about the emergence of resistant pathogens, particularly in areas of the world that rely on this medicion to treat onchocerciasis.

“Ivermectin should be the last choice, whether topical (for still-infested persons) or oral (especially for mass treatment),” they wrote. “Management should also include more frequent checking for head-louse infestation in families and schools.”

First-line therapy consists of 1% permethrin or pyrethrin insecticides, as recommended by the American Academy of Pediatrics in it’s 2010 guidelines. However, emerging resistance to these head lice treatments highlight the need for new and alternative therapies.

“If resistance in the community has been proven or live lice are present 1 day after the completion of treatment, a switch to malathion may be necessary. Other options include wet combing or treatment with dimethicone or other topical agents, depending on the availability of the agents in the country,” Chosidow and Girardeau wrote. “Nit removal is useful.”


  1. Pariser D et al. N Engl J Med 2012; 367: 1687-1693.
  2. Chosidow O, Giraudeau B. N Engl J Med 2012; 367: 1750-1752.