A Super Bug Spawns Concern — and a Cottage Industry

by Jennifer Ford

Lice infestation is no new bugaboo. Scientists used to believe that Christopher Columbus and his crew brought lice to the Americas, but the discovery of preserved lice in the hair of 1,000-year-old mummies in Peru proves that head lice have been making people itch for ages. This finding suggests that lice traveled from Africa up to 15,000 years ago. Columbus may be off the hook, but we still have a problem on our hands — and in our hair.

What Are Lice?

Head lice, or Pediculus humanus capitis, live on the scalp and feed on blood. Lice infestation, or pediculosis, affects millions of people a year, typically school-age children. Lice have no wings and do not jump or fly, so they spread through head-to-head contact or contact with clothing, bedding and furniture where lice have fallen.

The louse life cycle occurs in three stages: the nit (the egg, which the adult attaches to a strand of hair), the nymph and the adult.

Even in adulthood, lice grow only as large as the head of a pin. And anyone can get lice. "Having lice has nothing to do with cleanliness — in fact, lice love clean, loose easy-to-walk-through hair!" says Mary Nealon, NP, a pediatric nurse practitioner at Columbia University Medical Center in New York.

Treatment and Pesticide Resistance

For decades, traditional treatment for lice has centered on over-the-counter shampoos containing pediculicides, followed by combing with a fine-toothed comb designed to remove the organisms. Rid, active ingredient pyrethrum, and Nix, active ingredient permethrin, are two such shampoos.

As early as 1999, however, research showed that lice in the United States were becoming resistant to permethrin.¹And a study published in 2003 confirmed a genetic mutation that caused complete resistance to this pediculicide.²No resistance to pyrethrum has been documented.

Parents who have used these products can confirm their ineffectiveness. "We have found neither product to be generally effective," Nealon says.

Given the problems with resistance, today's treatment recommendations for lice vary, explains Jeanne Findlay, NP, who specializes in pediatric dermatology at Johns Hopkins University in Baltimore.

Findlay typically chooses a prescription-strength cream containing permethrin (Elimite) and provides explicit verbal and written instructions about application. She believes that a combination of methods is the best treatment. "Careful combing alone is not effective in getting rid of lice; it is the best way to catch them," she emphasizes.

Chronic lice infestation seems by anecdotal evidence to be more prevalent, as more and more parents pull their hair out over infestations that last for months and spread through entire families. When repeated treatments using over-the-counter methods fail to eradicate lice, desperate parents seek help from a health care provider, who can prescribe stronger pediculicides.

More effective treatments are linked with increased risk. Lindane (sold as Kwell) has been used in the United States for years.

Lindane is in the DDT family, and it is a potent neurotoxin. The Food and Drug Administration and Environmental Protection Agency (EPA) have warned of serious adverse health effects with lindane use: pulmonary edema, neurologic effects and liver and kidney damage.

Environmental concerns are issues as well. Because lindane is washed down sewer pipes, a single head lice treatment can contaminate up to 6 billion gallons of drinking water. Lindane is banned in 17 countries, and the EPA cancelled registration of lindane in 2006, with final use date set for Oct. 1, 2009.

Another common prescription treatment is Ovide, which contains the pesticide malathion. Malathion kills lice that are resistant to permethrin.²

Alternative options that do not contain pesticides are on the way. In March, phase I clinical trials were completed for a new topical treatment containing ivermectin (Stromectol in pill form), a compound produced by bacteria used to kill intestinal worms, mites and plant pests. The trials showed that ivermectin killed 100% of live lice, even those resistant to permethrin, but results on nits were not as significant. If this drug is approved by the FDA, it could be a useful alternative to other pediculicides because it is not readily absorbed into the skin.

And Eli Lilly is developing a low-toxicity lice treatment called Natrova, which will use spinosad, a bacterial fermentation byproduct approved as an organic insecticide. Spinosad kills lice by overstimulating the nervous system. Natrova is in clinical trials.

Other Reasons for Failure

The failure of pesticides is not the only reason that lice returns. Other possible reasons for treatment failure are misdiagnosis, noncompliance, new infestation or lack of ovicidal properties. These should be ruled out before resistance is assumed.

"One interesting thing to note is that if you read the instructions on Nix, it does not say that you should not shampoo for 3 days after using it," Nealon explained. "However, [the Centers for Disease Control and Prevention] say that in order to maximize the licicidal effects, you should refrain from washing with shampoo for 3 days. So if the general consumer does not know this — and most don't — then you wash away active ingredient before it's had its maximum effect. This could be one of many factors that have contributed to increasing resistance."

The fact that lice have begun mutating to resist certain pediculicides also suggests that the bugs may mutate further, becoming resistant to all pesticides.

This, in addition to the health risks associated with pesticide use, has prompted further study of the effectiveness of using pesticides to treat lice at all.³Experts including the National Pediculosis Society (NPA) discourage the use of any pediculicide or pesticide spray and recommend relying more on combing to remove lice.

Desperate Measures

Desperate parents have gone to extreme lengths to rid their children and homes of lice without using pediculicides.

"Back in the '70s, when I first started practicing as an NP, gasoline, paint thinner and kerosene were popular head lice treatments" in the Midwest, Findlay said. Coating the hair with mayonnaise, petroleum jelly or olive oil and occluding it with a shower cap for several hours remains popular today.

But Findlay noted that a 2001 study demonstrated that a live louse placed in petroleum jelly for several hours was unaffected and just as alive as it was prior to the treatment.⁴Parents also pursue many other nonpesticide remedies. One study showed that Cetaphil lotion was 96% effective in suffocating head lice.⁵"Mayonnaise and peanut butter work on the same principle," Findlay said. Other precautions recommended by the NPA include washing all clothing and bedding in hot water, boiling combs and vacuuming carpets and furniture.

"We recommend OTC treatments available in health food stores, such as Zero Lice, a tea tree oil-based product," Nealon said. These natural products also contain ingredients such as neem oil, lavender and rosemary. "Because of the ineffectiveness of Rid and Nix, and their rare neurotoxic effects, it's just not worth it.

"In the end, whatever parents choose to use, we stress clearly that all nits need to be removed with combing and manual removal," Nealon explained. "Also, parents need to re-treat in 7 to 10 days, and follow-up has to occur vigilantly for a good 2 weeks."

The need for effective lice remedies has drawn the attention of a variety of entrepreneurs (see sidebar). One end product of this interest is a hair-dryer device called the LouseBuster, which is equipped with a large-tooth comb on the end of a hose. It blows air more forcefully, but at a cooler temperature, than an everyday hair dryer.

One study found that the LouseBuster killed lice and eggs in just one 30-minute treatment by drying them out.⁶The authors of the study stated that the LouseBuster killed 80% of live lice and 98% of eggs. Another newer tool is the LiceGuard Robi Comb, which emits an electric current that aims to electrocute lice.

Lice Rule the School

Schools face a formidable challenge as a result of lice. To help keep lice from spreading, many have implemented a "no-nit" policy under which children are required to stay out of school until they are lice-free. The NPA supports the idea of a no-nit policy for schools, but opponents argue that children are being unnecessarily kept out of class.

To cut back on the number of children barred from the classroom because of lice, some schools have turned to louse-removal businesses for help. Nealon provides NP services to a school that hired a professional louse-removal company, Licenders, to visit campus three times a year to check every child's head. Licenders uses its own nontoxic oils and a careful combing system.

"Out of 470 students in kindergarten through eighth grade, we can find as many as 20 cases in the fall and maybe 6 to 10 in the winter and spring," Nealon said. "We follow up each school-wide check with a communication to parents, letting them know that lice checks were done, how many cases were found and then remind parents to check students routinely. We also provide a list of recommendations for how to prevent lice."

If a child is found to have head lice between school-wide checks, the school examines classmates and any siblings in the school and offers to check family members. They also send letters home with every child in the grade.

The cost of treating lice — in dollars and time spent — is staggering. Parents spend an estimated $160 million each year on pediculicides. Schools lose money when children are kept out of the classroom, and parents lose wages when they must stay home with their lice-infested child. The average cost of hiring a louse-removal service is about $75 an hour. Parents without health insurance or who can't afford to seek help from a health care provider or louse-removal service are left to hours of combing if OTC treatments fail.

These circumstances can contribute to the spread of lice, and they are the reason that Maria Botham founded Pediatric Scalp Care Specialists (PSCS). The nonprofit organization provides free screening and treatment of head lice to underserved populations by visiting schools with a mobile unit.

PSCS also works to educate the public about head lice. Botham says that for each day a child must stay home from school because of lice, a school loses between $24 and $40 in public funding, which amounts to $500 million in lost funds yearly.

"We need to look at this on a global level," she declared. Botham believes that her services benefit school nurses and NPs: "We want to work with nurse practitioners to relieve the burden so they can get back to treating [illness]."

Botham plans to partner with school districts to obtain funding that will allow PSCS to provide services that will get children back to school.

New treatments are making lice manageable in a safer way. "I prefer recommending less potentially toxic products, since resistance is increasing anyway," Nealon says. "It seems pretty clear that lice are here to stay. Like other organisms, they are adaptable and thriving. It's important to help parents and children stay calm and remember that no long-term harm comes from having lice."

Nealon also emphasizes prevention and education: "Probably the best thing parents can do is buy their child his or her own athletic helmets, and what we as practitioners can do is invest in a good magnifying lamp and get familiar with what nits really look like!"

References

1. Pollack R. Differential permethrin susceptibility of head lice. Arch Pediatr Adolesc Med. 1999;153(9):979-1001.

2. Yoon KS, et al. Permethrin-resistant human head lice, Pediculus capitis, and their treatment. Arch Dermatol. 2003;139(8):994-1000.

3. Burkhart CG. Relationship of treatment-resistant head lice to the safety and efficacy of pediculicides. Mayo Clin Proc. 2004;79(5):661-666.

4. Burkhart CN, Burkhart CG. Recommendation to standardize pediculicidal and ovicidal testing for head lice (Anoplura: Pediculidae). J Med Entomol. 2001;38:127-129.

5. Pearlman D. Cetaphil cleanser (Nuvo Lotion) cures head lice. Pediatrics. 2005;116(6):1612.

6. Kersten H. Hot air is an effective treatment for head lice. J Pediatr. 2007;150(5):562-563.

Jennifer Ford is the associate editor. Reach her at jford@merion.com.

The American Spirit: From Problem to Opportunity

In response to resistant and chronic lice, "nit-picking" businesses are growing in the United States. Louse-removal services range from combing to combing plus additional treatments, and many health insurance plans will cover the cost.

Peggy Warner, RN, started The Texas Lice Squad after a particularly harrowing experience with lice in her own family. She doesn't use pesticide-based shampoos.

"We use an enzyme solution that breaks down the glue that is used to attach the eggs to the hair strands," she explained. "We then comb out the eggs, the adult lice and the nymphs. It is a very time-consuming process — an average treatment takes 2 to 3 hours. However, 99% of the time we only need to do one treatment."

One of the largest louse-removal businesses is Hair Fairies, which started in San Francisco and has expanded to include locations in Los Angeles, New York and Chicago. The company's CEO, Maria Botham, told ADVANCE that Hair Fairies plans to open franchises in 2008.

A number of other louse-removal businesses are capitalizing on the lice problem. A network of Orthodox Jewish women in New York provides louse-removal services in offices or in client homes. And Hair Whisperers in Los Angeles makes house calls to remove lice from hair and homes.