New anti-lice lotion is good news for nitpickers

ARCHIVED CONTENT: As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date each article was posted or last reviewed. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician. 

The FDA’s approval this week of an old drug called ivermectin for treating head lice comes as good news to folks who shudder at the thought of using a nit comb to remove lice. It will be sold as a lotion under the brand name Sklice.

Ivermectin works by interfering with nerve and muscle cells in invertebrates like the common louse, causing paralysis and death. It appears to work against both the flea-like adults and nits—the eggs that lice attach to hair shafts.

According to Sanofi, the drug’s manufacturer, a single 10-minute application of Sklice gets rid of lice without having to comb out nits. Sklice joins Natroba, another no-comb medication, which was approved a year ago.

The clinical trials on which the FDA based its approval included nearly 800 people ages six months and older. While that’s a decent size for testing whether a new treatment is effective, it’s tiny for evaluating whether a drug is safe. However, ivermectin has been used for years as an oral medication to help prevent and treat river blindness (onchocerciasis), a scourge in many African and Latin American countries. Its safety record as an oral medication is good.

If you’d rather not use drugs or chemicals to fight lice, don’t ignore the value of a nit comb. As I wrote last year, a study published in the British Medical Journal in 2005 showed that combing out the hair with a fine-toothed comb (the “Bug Buster”) immediately after using conditioner worked better than a single treatment of an over-the-counter insecticide.