Single ivermectin application is effective

One 10-minute at-home application of topical ivermectin eliminates lice-without combing-in most patients within 1 day, a recent investigation showed.

Two parallel studies were conducted simultaneously in 765 patients at 16 sites in 12 states during a 5-month period. Eligible patients were aged at least 6 months and had a minimum of 3 live lice on their hair or scalp.

Once investigators identified an index patient in a family, they also enrolled into the study any other household members with at least 1 live louse. Families at each site were divided into 2 groups: 1 group received a tube of lotion containing 0.5% ivermectin and the other group an identically formulated lotion without ivermectin (control group). Participants were instructed to apply the lotion to their hair and scalp and leave it on for 10 minutes before rinsing the hair with water.

One day after application of the lotions (day 2 of the study), 94.9% of patients who received lotion with ivermectin were louse free compared with 31.3% of those whose lotion contained no ivermectin. Similarly, significantly more patients in the ivermectin group than in the control group were free of live lice at subsequent observations: 85.2% versus 20.8% at day 8 and 73.8% versus 17.6% at day 15. In addition, topical ivermectin was not associated with increased frequency or severity of adverse events (Pariser DM, et al. N Engl J Med. 2012;367[18]:1687-1693).

Commentary

Do you prescribe more treatment for head lice now than you have in the past? If information on resistance to over-the-counter permethrin and pyrethrins preparations is accurate, more patients with this condition should be consulting you about prescription alternatives. You now have several options, including oral ivermectin (off label) and topical malathion, spinosad, or benzyl alcohol, in addition to this new offering. It will take some time and head-to-head studies to determine which of these is the most effective, affordable, and convenient choice. Stay tuned.  -Michael Burke, MD