LITTLE ROCK — The mere thought of head lice crawling around a child’s scalp is enough to generate shudders of disgust. Judging from the drastic measures some parents take to get rid of them - from mayonnaise and vinegar to overdoses of potentially toxic chemicals - you’d think they were the worst scourge on earth.
Yet aside from the ick factor and a sometimes itchy scalp caused by an allergic reaction to their saliva, head lice cause no physical distress and transmit no diseases. In a clinical report issued in July by the American Academy of Pediatrics, the organization noted that head lice cause “a high level of anxiety among parents of school-aged children.”
A bigger problem than the lice is that infestations are commonly misdiagnosed. By some estimates, at least half of the young children treated for head lice - even forbidden to attend school, in some cities and states with “no nit” policies - no longer have them or were never infested.
Schools that check children for lice often rely on nurses and parents ill-equipped to detect an active lice infestation. In one study of more than 600 samples of presumed lice or eggs submitted by teachers, parents, nurses and physicians, about two-thirds turned out to be dandruff, scabs, dirt, plugs of skin cells, hair spray droplets, other insects or eggs that were no longer viable or hatched.
This study, by Dr. Richard J. Pollack and colleagues at the Harvard School of Public Health, concluded that “noninfested chil-dren become quarantined at least as often as infested children” and that treatments with louse-killing insecticides “are more frequently applied to noninfested children than to children who bear active infestations.”
In the words of the pediatrics academy, “a child should not be restricted from school attendance because of lice; no-nit policies should be abandoned.” And “routine classroom or schoolwide screening should be discouraged.”
Anyone can get head lice.They have no respect for social class, hygiene, hair length or frequency of brushing. They are most often transmitted by direct head-to-head contact, far less often by exposure to the clothing, hats, helmets, hair accessories, headphones or furnishings used by an infested person. Children are more often infested than adults, and whites more so than other groups.
While “it is probably impossible to prevent all head lice infestations,” the pediatrics report stated, “it is prudent for children to be taught not to share personal items such as combs, brushes and hats. However, no one should refuse to wear protective headgear because of fear of head lice.”
Lice are blood-feeding parasites that crawl but cannot fly, hop or burrow into the scalp. Nor can they survive more than a day or so away from the blood and warmth of the human scalp. Females lay about six eggs a day that are cemented to hair shafts right next to the scalp. Only fertile eggs, or nits, will hatch, but even they cannot hatch at temperatures lower than those near the scalp.
DETECT LIVE LICE, THEN TREAT
“The gold standard for diagnosing head lice is finding a live louse on the head,” the academy report stated. This can be tricky because the insects are tiny - from the size of a strawberry seed to about one-eighth of an inch - and they avoid light and can crawl quickly. The best place to look is at the nape of the neck and behind the ears.
Finding eggs is often easier, but they may not represent an active infestation that warrants treatment. Pollack explained that magnification and good training are the tools usually needed to distinguish between a nit that houses a live embryo and one that is nonviable, empty or dead.
Thus, like the pediatrics academy, he says treatment should be considered only when active lice or viable eggs are spotted.
“Itching of the scalp or the perception that something is crawling on the head does not warrant treatment for lice,” he said.
Even when live head lice or viable eggs are found on someone’s scalp, “herculean cleaning measures” are not necessary, according to the recent report on the problem by the American Academy of Pediatrics.
While it is prudent to clean the bedding, bedclothes and hair care items used by the infested person, the report stated, “only items that have been in contact with the head of the person with infestation in the 24 to 48 hours before treatment should be considered for cleaning.”
If one person in the home is infested with head lice, all household members should be checked, but only “those with live lice or nits within 1 centimeter of the scalp should be treated.”
Washing or drying items at temperatures above 130degrees Fahrenheit will kill stray lice or nits. Items that cannot be washed can be drycleaned or bagged in plastic for two weeks. Furniture, carpeting, car seats and other fabric-covered items can be vacuumed.
As for home remedies like mayonnaise and vinegar, there is no reliable evidence of their effectiveness. Various “natural” products - oils and herbal remedies - are not required to meet federal standards for safety and effectiveness.
Other chemical products have been studied, and the results are mixed.
IT’S FINE TO NITPICK
And what about removing live eggs with a metal fine-toothed comb - better known as nitpicking?
It is tedious but can be effective. Nitpicking is easiest to do on wet hair treated with conditioner, and it should be repeated after a week or so. There are also commercial nitpicking salons in some areas of the country and individuals who charge by the head or hour.
Guidance that Pollack developed to manage lice infestations at home and school can be found at identify.us.com/head-lice/headlice-document-download. The California Department of Public Health has an illustrated guide for parents that can be found by doing a Web search for “head lice parents guide.”
Family, Pages 33 on 09/29/2010