Prescription medication may be needed to treat some attacks by lice, which scientists say have now become resistant to over-the-counter treatments in California and 24 other states.
Researchers presented the head-scratching findings at Tuesday's 250th National Meeting and Exposition of the American Chemical Society in Boston.
The study's author Kyong S. Yoon, an assistant professor at Southern Illinois University, identified products such as ivermectin and spinosad, both of which require prescriptions, as possible effective agents in killing the current breed of lice.
There's more bad news: there's no evidence that "nit pickers," the fine-toothed combs that some parents use, work to remove lice, Dr. Bernard Cohen, a professor of pediatrics and dermatology at the Johns Hopkins Children's Center, told TODAY.com.
"There have been a couple of nice studies showing that nit picking doesn't really work," he said.