Head lice are a terrible part of the school year for an estimated 6 to 12 million children in the United States every year. Infestations can lead to itchy scalp, irritability and poor sleep.
Making matters worse, the vast majority of states are overrun with head lice that are resistant to common over-the-counter treatments, TODAY reports.
According to a new report published in the Journal of Entomology, in 42 out of the 48 tested states, 100 percent of lice tested have evolved to be resistant to the effects of pyrethroids and pyrethrins, the active ingredients in most over-the-counter concoctions.
However, this doesn’t mean the over-the-counter treatments are completely ineffective.
“This mutation makes them somewhat insensitive. But in most cases pyrethrins and pyrethroids can still kill lice with the mutation, if you apply way more of the compound,” Kyong Sup Yoon, an assistant professor in the department of biological sciences and environmental sciences at Southern Illinois University Edwardsville, said.
Some parents are taking their children to “nitpickers,” who manually remove the insects from hair using combs and sometimes just their fingers.
Researchers say you shouldn’t give up on over-the-counter treatments just yet.
You might have to use the over-the-counter treatment twice before it works.
“Treat the entire head and leave it on for a few hours and then repeat a week later,” Dr. Robin Gehris, chief of pediatric dermatology at the Children’s Hospital of Pittsburgh, told TODAY. “If you still see things moving after the second treatment it’s time to call the doctor.”
There are also some prescription treatment options, including Sklice, Ovide and Natroba. All use different types of chemicals than permethrin and pyrethrin, and thus lice that are resistant to over-the-counter treatments should not be resistant to them.