Drug-Resistant Head Lice In At Least 25 States, Report Finds

BOSTON (CBS) – Drug-resistant head lice are now in 25 states, including Massachusetts, according to new research.

The findings, presented at a meeting of the American Chemical Society in Boston Tuesday, show that people have been treating the bug with over-the-counter medications for so long that the lice have become immune to it.

"We are the first group to collect lice samples from a large number of populations across the U.S.," researcher Kyong Yoon said. "What we found was that 104 out of the 109 lice populations we tested had high levels of gene mutations, which have been linked to resistance to pyrethroids."

Pyrethroids include permethrin, which is the key ingredient in many common lice treatments.

States in pink have drug-resistant lice (Image credit Kyong Yoon, Ph.D.)

Fortunately, researchers said lice can still be treated with different medications, including prescription-only treatments.

"The good news is head lice don't carry disease," Yoon said. "They're more a nuisance than anything else."