Head Lice: Two New Treatments for the Stubborn Bugs
When children bring home head lice – between six and 12 million American schoolchildren do each year - the first line of defense is usually a treatment of a pyrethoid-based product such as Nix or Acticin. Lice can become resistant to these products, so researchers are looking for new methods to finally “Rid” kids of these pesky bugs.
Head lice tend to affect younger, school-aged children and girls are more likely to get infested than boys. The most common sign of head lice is an itchy scalp and red bumps in the skin. Close examination of the hair and scalp will show evidence of the egg casings (nits) attached to the hair shaft as well as live lice. After the nits hatch, they can live about 30 days and produce even more eggs.
The first treatment prescribed for head lice are over-the-counter products that contain a neurotoxin called permethrin. These are left on the hair for 10 minutes and washed out. However, one study found that this only killed about 5 to 7 percent of the lice and the bugs can develop a resistance.
A new product called Ulesfia, manufactured by Shionogi Pharma Inc in Atlanta and approved by the FDA in 2009, has an active ingredient of 5% benzyl alcohol which suffocate the bugs. Clinical trials of 250 children with head lice found that 91% of those given Ulesfia had no lice on Day 8 and 75.6% had none on Day 14 of the study. The most common side effect was irritation at the application site.
Unlike other over-the-counter products, it contains no neurotoxic pesticides and has been shown to be safe for children as young as 6 months. Resistance to the medication is also not likely to be an issue.
When lotions and shampoos are not effective, researchers from the Hopitaux de Paris have found that an oral medication may be useful.
The study involved 812 people from 376 households in 7 different parts of the world. The participants, all at least 2 years old and average age of 10, had head lice that were resistant to a topical insecticide several weeks earlier.
Part of the group was given a scalp application of 0.5% Malathion (Prioderm Top), a lotion that contains insecticide. The intervention group received two doses of an oral medication called ivermectin, which is a drug used to prevent heartworms in dogs and has been successful in treating scabies. The doses were given seven days apart.
After 15 days, the researchers found that those receiving ivermectin were 95% lice-free, while the Malathion group was 85% free of the bug. Patients also preferred the oral treatment to the lotion, which had to be left in the hair for 10 to 12 hours before washing out.
Ivermectin was found to be 10% more effective than Malathion in killing the lice. The medication works by disabling the louse nerves from communicating. The brand name of Ivermectin is called Stromectal and is made by Merck.
The study did have one serious and one mild adverse event during the trial. A 7 year old girl had a seizure six days after the first dose of Stromectal, was hospitalized, and given epilepsy medication. An 11 year old girl had a severe headache six days after the first application of malathion but fully recovered.
To prevent head lice, children should not share combs, brushes, hats, barrettes, or other personal care items. When a family member is infected, wash bedding, pillowcases, and brushes in hot water.
Although tempting, natural home remedies are not likely to be effective in completely ridding head lice. Mayonnaise, olive oil, and petroleum jelly are sometimes used to suffocate the lice. However, the bugs have an external structure for breathing called spiracles that close to protect the bug. After the treatment is removed, the bugs have a “resurrection” and can begin biting and reproducing again.
Sources: The Ulesfia study is published in the January-February issue of the journal Pediatric Dermatology. The Ivermectin study appears in the March 11 issue of the New England Journal of Medicine.