As head lice continue to evolve, the efficacy of some older, standby treatments has dwindled. One promising topical medication is on the horizon, pending approval by the Food and Drug Administration. But there is no way to predict how long such treatments will remain useful.
He cites lice as the initial reason for the so-called "butch" haircuts given to military recruits.
Those methods are a bit drastic for dealing with the head lice reported in millions of school-age children every year. Still, Dr. Burkhart tells Dermatology Times, removing the hair remains one possible way of eliminating the problem. Barring that, the clinical professor at the University of Toledo College of Medicine says effective treatments for lice are limited, although investigation is currently under way for new therapies.
"Over-the-counter (OTC) products like Rid (Pfizer) and Nix (Insight Pharmaceuticals) used to work extremely well in the '80s. In fact, (they were) so good that several prescription products like Ovide (Medicis) left the market," he says. "As time went by, however, the insects - which have the genetic capability of circumventing whatever agent we give them - developed resistances. Depending on the community, and sometimes the environment, these OTC products may only work 30 to 65 percent of the time."
The other long-time standard treatment was lindane, but Dr. Burkhart says there are so many restrictions on that product - including patients who have suffered head trauma, have been on penicillin or other antibiotics, or who suffer from seizures or atopic dermatitis - that its use is limited.
Some reported side effects have also been severe, such as rashes, burned skin and seizures or death after prolonged use.
"I think the Food and Drug Administration (FDA) decided to allow the availability of lindane because we don't have a lot of approved insecticides. If they had taken it off the market entirely, people would have been left with even fewer options," Dr. Burkhart says.
Alternate tx methods
Some organizations, including the American Academy of Pediatrics, have suggested suffocating lice with various household materials, such as mayonnaise, olive oil or Vaseline, and sometimes wrapping the head in plastic wrap for hours.
The problem is that while the lice may appear to be dead, Dr. Burkhart says often they survive the treatments.
"People fail to realize that you can put these lice in oil or Vaseline, take them out, put them out to dry on a piece of paper and they will start moving around again. Lice die because they dehydrate. They usually get hydrated with a blood meal, but they can survive if they are kept hydrated by humidity or moisturizing agents."
Dr. Burkhart suggests that doctors could test whether these home remedies work by placing the removed lice on a paper after treating them, and observing whether they resume activity.
Another misconception is that head lice can only be transmitted by direct contact, such as use of another's comb.
Dr. Burkhart explains that fomite spread can actually cover distances between people.
"Researchers have now shown that electricity can spread the lice a meter away when someone just combs their hair. Hair dryers can blow lice onto another host," he says.
According to Dr. Burkhart, the most effect treatment currently available for head lice is Ovide, a prescription medication that contains two insecticides.
Still, he warns that the lice can be expected to develop a resistance to that medication, also.