Head Lice Getting Ahead of Treatments, Officials Fear

At one Irvine school, the situation was lousier last fall than ever before--37 students and a teacher found with head lice, as opposed to the usual fewer than 10 cases in an entire school year.

And some of the cases seemed especially hard to cure. One Irvine student’s problem was so perpetual that he missed 25 school days.

“Some kids keep coming back with lice,” said school district nurse Sally Valentine, “and their parents are apparently religiously trying to treat the situation.”

The latest word from the public health front offers little comfort to school officials. Ordinary head lice may be turning into “super lice,” developing resistance to over-the-counter treatments that are parents’ chief weapon against the repulsive bloodsuckers.

This might explain why head lice infestations--which medical historians trace back at least 9,000 years--seem to be on the upsurge.

“I’d say there is a definite increase,” said Dr. Vicki Kramer with the California Department of Health Services, who deals with public schools and health departments on head lice.

“I’d say we have a 20- to 30% increase in the number of calls in the last year.”

Kramer believes resistance--the medical term for this type of immunity--is a factor.

“If the lice are harder to get rid of, people are carrying them for longer periods of time,” she said. “And that increases the chance they will infest someone else.”

Sally Valentine agrees. She has seen more chronic lice cases over the past two years than in all her previous six years with the district.

After the outbreak at an Irvine school last October, custodians were asked to scrub the floors and desks more frequently, and boys’ and girls’ Scout troops and Little League teams were also advised to check for lice infestations.

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In Agoura Hills, another well-to-do suburb in the western San Fernando Valley, teachers were sending home as many as 15 students a day in 1995.

Neither county nor local school officials keep records on head lice outbreaks--most medical authorities regard head lice as nuisances and do not track them like disease.

But complaints from school health workers started coming into public health offices a couple of years ago that widely used over-the-counter remedies--pesticides approved for use on the scalp--weren’t working as effectively as they had in the past. But with no solid evidence, scientists and drug industry researchers initially dismissed the idea.

Lately, however, some key researchers have become believers.

“We’ve been getting reports from school nurses from all over the country,” said Terri Meinking, a University of Miami researcher who co-wrote a landmark 1996 report on a head lice treatment. “When they say it doesn’t work the way it used to, we have to take that seriously.”

The California Department of Health Services alerted local public health agencies last year that “there is circumstantial evidence that head lice are becoming increasingly resistant to commercially available chemical treatments.”

Scientific study of the problem is underway at Harvard University. Dr. Andrew Spielman, a professor of tropical public health who is overseeing the project, said he hopes the research into head lice resistance will be completed this fall.

Researchers in Israel, however, have already completed a similar study that found head lice had indeed developed a resistance in general to pyrethroids--the family of chemicals used in most over-the-counter remedies--and in particular to permethrin, which is used in Nix, by far the most widely used brand in the United States.

“The results suggest that resistance to pyrethroids has developed rapidly among head lice since permethrin was introduced (in Israel) in 1991,” the researchers wrote in a report published in the British journal Medical and Veterinary Entomology.

Warner Lambert, Inc., which makes Nix, dismissed the Israeli findings.

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The Israeli study tested only permethrin, the key active ingredient in Nix, but not the whole formula, which contains several substances, said Dr. Judith Sills, senior director of product safety surveillance and information at Warner Lambert. If Nix doesn’t work, it’s because parents aren’t using it correctly, she said.

“I don’t believe they demonstrated true resistance,” she said.

But Spielman, whose research at Harvard also focuses on permethrin, said the Israeli work “looks like a reasonable study.”

“If there’s physiological resistance to the active ingredient, that’s really saying something,” Spielman said. Even if a product contains other helpful substances, “the problem would still be grave.”

Enough evidence has surfaced that at least one drug industry figure conceded resistance is probably real.

“We have to assume there is growing resistance out there,” said Harry Upton, president of Care Technologies, which produces the Clear line of head lice treatments. “Or at least an awful lot of misapplications.”

But a number of Orange County health officials say many variables factor into lice reinfestations. Eradicating the problem is a time-consuming and meticulous procedure, authorities said.

Parents are told to thoroughly wash their children’s hair and pick out the nits, or lice eggs, from the scalp with a special, fine-toothed lice comb. Also, the heads of siblings must be checked, the house must be vacuumed, linens washed, car seats and sofas cleaned, and stuffed animals bagged for at least a week to kill any lice on the toys.

“It’s a very frustrating experience,” said Irvine parent Laurie Marrujo, who spent half a day hand-picking the nits from her daughter’s hair, and another two days cleaning her entire house and calling the girl’s friends to warn their parents.

“One louse can lay 200 eggs,” said Landry, who doesn’t believe the parasites are becoming immune to treatment products. “If you don’t do exactly what is needed, the lice will reinfest.”

Even more, products not applied properly won’t be effective, she said.

For instance, RID, another over-the-counter remedy, must be applied to dry hair to effectively attack the lice’s upper respiratory system.

“If you pour RID to a wet head, the lice will close off their respiratory system and are able to do so for a period of time, protecting them from the treatment,” said Justin Bower, a health manager for Pfizer Pharmaceuticals, which manufactures RID.

And the problem is by no means confined to poor neighborhoods, health officials said.

“Lice don’t discriminate,” said Sandy Landry, health and wellness administrator for the Orange Count Department of Education’s health services. “It doesn’t favor an economic class or cultural group. You could go to the movies, sit in the lounge chair and pick up lice.”

Last year, sales of lice-fighting product Nix grew by a whopping 52% to reach $42 million, according to Leslie Hare, a spokeswoman for Warner Lambert. Hare said the increase does not so much reflect a rapid rise in head lice cases as it does increased distribution and a successful marketing campaign.

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Promotion is one of the problems underlying resistance, if it in fact exists, according to the National Pediculosis Association (the Latin name for head lice is Pediculus humanus capitis), a nonprofit group based near Boston.

“The industry from the beginning has put out information that has caused confusion and the abuse of the chemicals commercially available for children who get lice,” charges Deborah Alschuler, founder and head of the association.

Because drug companies have given their products benign images, “People perceive these products to be shampoos and cream rinses,” and overuse them, Alschuler said. “That sounds nice, but these are pesticides.”

Adults are so repulsed by head lice they sometimes take dangerous measures.

“We still get reports of parents using kerosene,” said communicable disease nurse Lori Nelson, of the L.A. school district’s Reseda office.

Far worse, an Oklahoma City man tried to kill head lice on a 6-year-old girl by washing her hair with Diazinon, an agricultural-strength pesticide, police there reported last week. The girl, who went into full cardiac arrest, was revived but was hospitalized in serious condition and may, doctors said, have permanent injuries.

What’s the alternative if over-the-counter remedies don’t work? Some physicians are prescribing stronger does of permethin, a 5% solution compared to the 1% in Nix. But if lice are becoming resistant to the weaker solution, it’s likely they’ll resist the stronger dose eventually as well, researchers warn.

Meinking, at the University of Miami, said there is hope for the future from entirely new louse-killers still in the testing stage. “We are working on new treatments that will have active ingredients that are not pesticides,” she said. “We are on the road to some very exciting things.”