Well, this certainly isn’t good news.
The American Chemical Society recently reported a new study shows that certain lice in at least 25 states are now resistant to over-the-counter (OTC) treatments.
Study author Kyong S. Yoon, PhD, assistant professor in the Biological Sciences and Environmental Sciences Program at Southern Illinois University, has been researching lice since 2000. His research is still ongoing, but what he’s found so far in 109 samples from 30 states is startling: the vast majority of lice now carry genes that are super-resistant to the OTC treatment used against them.
Permethrin, part of the pyrethroid class of insecticides, is the active ingredient in some OTC treatments. Certain lice have developed a trio of mutations that make it resistant to the pyrethroids. What happens is you end up with a new kind of super-lice that doesn’t respond to typical treatment any longer.
“It’s a really, really serious problem right now in the U.S.,” Yoon says.
Six million to 12 million U.S. children are infested with head lice every year, "with parents spending about $350 million dollars annually on permethrin-laced over-the-counter and prescription treatments," Yoon said. Lice infestations occur in rich neighborhoods as well as poor ones.
Currently, there are 25 states, including Arizona, California, the Carolinas, Connecticut, Florida, Georgia, Illinois, Maine, Massachusetts, Texas and Virginia where lice have what Yoon calls "knock-down resistant mutations". This involves a triple whammy of genetic alterations that render them immune to OTC permethrin treatments.
Lice in four states, New Jersey, New Mexico, New York and Oregon, have developed partial resistance, the researchers found.
Michigan's lice have no resistance as yet. Why that is remains unclear.
Fortunately, there are prescription medications that still work in treating lice. They are more expensive than over-the-counter formulas and do not contain permethrin. These prescriptions may contain benzyl alcohol, ivermectin, malathion and spinosad; all powerful agents or insecticides. Lindane shampoo is another alternative for difficult-to-treat cases.
If your child has head lice and OTC medicines haven’t worked, you can check with your pediatrician or family doctor for a prescription treatment.
Sources: Mandy Oaklander, http://time.com/4000857/lice-treatment/
Alan Mozes, http://health.usnews.com/health-news/articles/2015/08/18/head-lice-now-resistant-to-common-meds-in-25-states