There's a new addition to the arsenal of weapons against head lice and "super lice," which have developed a resistance to the active ingredients in common over-the-counter treatments.
The U.S. Food and Drug Administration on Friday approved Xeglyze, a new medicine to get rid of the little parasites in patients who are at least 6 months old.
The formulated lotion, available by prescription, has been shown to be "100% effective" in killing topically-treated eggs from DDT- and permethrin-resistant head lice, said John Clark, professor of environmental toxicology and chemistry, and director of the Massachusetts Pesticide Analysis Laboratory at the University of Massachusetts Amherst.
It works by deactivating certain processes necessary "for efficient egg hatching," Clark told TODAY. Given this new approach and its effectiveness, the new drug diminishes the chance of cross-resistance to previously-used treatments and promises to have a longer useful lifetime, he added.
Lice Clinics of America is reporting an uptick in cases this spring, with its clinics seeing an average increase of 25% in lice activity from April to May. Infestations affecting the entire family have been more severe during the pandemic, the company said in a statement this month.
Some communities — including parts of Texas, California, Louisiana and Kansas — saw even higher numbers, with increases of up to 50% in lice activity, which Dr. Krista Lauer, a family physician and the company’s medical director, called “shocking.”
The numbers are based on reports from the company’s clinics that were open in April and May — 112 of about 200 across the country at the height of the lockdown, she noted.
“When the stay-at-home mandate happened, kids who had head lice that had not been identified yet were then sequestered in their home with their entire family,” Lauer told TODAY.
“Where normally, maybe the primary caregiver or sibling would also get infested when a child comes into the home, what was happening with the increased home orders was that the penetration within the household was significantly greater. So instead of seeing one other person in the household who was positive or possibly two, we were seeing the entire household being affected.”
The level of infestation was also much more severe because it went longer without being managed, she added.
Then when the lockdown eased, some of those affected people perhaps hugged friends or loved ones they had not seen for a long time, allowing “very rapid transfer” of head lice to others, Lauer said.
The age of ‘super lice’
The little parasites feed on human blood and live close to the human scalp.
In the U.S., head lice infestations are most common among pre-school children in child care, elementary schoolchildren and household members of infested children, the Centers for Disease Control and Prevention (CDC) noted. Lice Clinics of America usually sees a jump in cases in September when kids go back to school, Lauer noted.
Symptoms include itching and the feeling of something moving in the hair.
The insects are spread by direct contact with the hair of an infested person, the CDC noted, and personal hygiene or cleanliness in the home has nothing to do with getting head lice.
Non-prescription treatments are available, but many parents have found such lice-killing shampoos or cream rinses have failed to work, the American Academy of Dermatology noted.
That’s because most states have been overrun with "super lice" that have developed a resistance to the active ingredients in common over-the-counter treatments, a 2016 study found.
“They are a huge problem,” Lauer said. “Over time, their prevalence has increased.”
In fact, the effectiveness of OTC preparations had declined to 25%, a review article published in Pediatric Dermatology found.
If a full course of an over-the-counter treatment fails, the CDC advised parents to contact their health care provider. Several medications are available by prescription.
Some doctors advise going straight for the stronger treatment.
Parents who discover lice in their children’s hair should just call their pediatricians and ask for a prescription to be called in to the local pharmacy, Dr. Kenneth Polin, a pediatrician at Lurie Children’s Hospital of Chicago, previously told TODAY.
“You have to understand what the family is going through,” he said. “There’s a huge psychological impact.”