Head lice are especially common in children in
crowded areas like schools. Local medications like permethrin and pyrethrins
are commonly used to treat head lice, though lice are now getting resistant to
these treatments. The other options include lindane and malathione, which have
questionable safety in children and have an unpleasant odor. Benzyl alcohol and
spinosad are other two newer drugs recently approved for the treatment of head
drug used to treat worm infestations and scabies, has also been found to be
effective in lice infections
. Moreover, the oral medication has been found to be
useful in the treatment of resistant lice infections. A topical or local
preparation of ivermectin could be a good option for the treatment of head lice
infections and at the same time, the side effects of oral medications can be
A recent paper describes the efficacy and safety of
0.5% ivermectin lotion when used in two clinical trials of head-louse
infestation carried out in different states of America. All the patients were
found to have at least three or more live lice on the scalp or hair before the
start of treatment. The patients were given a tube that contained either
ivermectin or a vehicle control for the comparison of results. The lotions were
to be applied to the hair and scalp for 10 minutes on a single occasion.
Adverse effects were assessed by a physician. The efficacy and safety of the
drug were evaluated on days 2, 8 and 15 of the study.
The researchers found that out of the 765
individuals who completed the study, topical ivermectin was significantly more
effective in treating head lice as compared to the vehicle control; in fact 94.9% patients were louse-free after 1 day
. However, this percentage reduced over the next two
assessments (85.2% on day 8 and 73.8% on day 15). This may be due to improper application of the lotion, inadequate
exposure of the lotion to louse eggs and re-infestation from other sources.
Itching was significantly reduced in patients
applying ivermectin lotion.
Side effects like itching, excoriation of skin and
redness were sometimes noted, but these were slightly more common in the group
that was administered the vehicle. One patient complained of pain in a limb
with the vehicle. Side effects probably
attributable to the ivermectin included eye irritation and skin-burning
Thus, according to the researchers, topical
ivermectin appears to be as safe and effective novel method for the treatment
of head lice infestations.
1. Topical 0.5% Ivermectin Lotion for Treatment of Head Lice; David M.
Pariser, M.D et al; N Engl J Med 2012; 367:1687-1693November 1, 2012