Lice

What are head lice?

They're tiny, wingless, parasitic insects that live on the scalp and suck blood, causing severe itching. The good news is that head lice don't carry diseases; they are more of a nuisance and not a threat to your child's health.

How will I know if my child has head lice?

There's a good chance a preschool teacher or elementary-school nurse will call with the bad news. But you can watch your child for frequent scratching, often the first sign of infestation. If your child scratches a lot, especially around the back of the head or the ears, check for lice immediately.

Lice aren't easy to see: the bugs take on the color of the hair they're hiding in. In fact, you may never see a louse. It's common to discover an infestation of head lice based on lice eggs (nits) alone. Nits are also tiny -- about the size of sesame seeds -- and creamy off-white or pearly white in color. It's easy to confuse nits with dandruff, but nits are attached to the hair shaft with a cement-like glue, not loose like dandruff.

How did my child get lice?

Probably from a classmate or a friend or possibly from shared clothes, such as a cap or a baseball helmet. It's a myth that lice are a product of poor hygiene or poverty. In fact, head lice are remarkably egalitarian and can spread and flourish even in the wealthiest communities.

Because lice travel easily from one head to another, getting rid of them right away prevents them from spreading to other family members, allows your child to go back to school quickly, and puts your family routine back on track.

How do I get rid of lice?

Most people turn immediately to commercially available lice, or pediculicide, shampoos. The treatment of choice is an over-the-counter lice shampoo with permethrin or pyrethrin (pyrethroids). Doctors usually recommend a product containing permethrin (called Nix). Permethrin is a synthetic form of pyrethrin, which is derived from chrysanthemums. Other commonly used brands contain pyrethrin in combination with piperonyl butoxide; brand names include A200, Pronto, and Rid. The American Academy of Pediatrics recommends permethrin or pyrethrin as a first-line treatment for lice because they are nontoxic to humans.

Keep in mind that shampooing once is unlikely to rid your child of lice. In fact, the Federal Trade Commission censured the makers of several commercial lice shampoos for false and misleading advertising. The companies claimed their shampoos were 100-percent effective with only one application. To ensure your child remains free of lice, you must follow up with a second permethrin or pyrethrin treatment seven to 10 days after the first. The second treatment is critical because the pyrethroid shampoo doesn't always kill all the nits in a single treatment.

Although pyrethroid shampoos used to offer desperate parents ready relief, an increasing number of parents say lice are no longer responding. Recent studies appear to document a rise in pesticide-tolerant lice. If treatment with over-the-counter pyrethroids doesn't work, consult with your child's doctor about further measures.

Malathion is a prescription treatment that is extremely effective against lice, but it is highly toxic if ingested. It also has an alcohol base that is flammable. Supervise your child carefully if you use malathion, and don't follow up with a second treatment seven to 10 days later unless you actually see more live lice.

Avoid products containing lindane for children under 3. This highly toxic insecticide has been linked, in rare cases, to convulsions and brain damage in children; lice are often resistant to lindane as well.

How do I apply a lice shampoo?

Here are the three basic steps for applying pyrethoid treatments:

1. Shampoo your child's hair with a fairly strong shampoo, such as Prell, to remove oil and styling products that might be coating the hair before using the lice remedy. Don't use conditioner; it also coats hair and protects the pests.

2. Let hair dry, then apply the lice shampoo. The instructions on the label will tell you how long to leave it in. Some doctors and school nurses recommend leaving the shampoo in for several hours or even overnight, but experts say there's no evidence that longer exposure makes lice shampoos more effective. It's important to remember that these shampoos contain pesticides and should be used sparingly.

3. Rinse out the lice shampoo and towel-dry hair. Again, avoid using a conditioner, especially after shampooing with Nix. (It has some residual action, and conditioners interfere with that.)

Within eight to 12 hours of treatment you may still see some live lice moving more slowly than before. This may be okay: the medicine can take a while longer to kill all the lice. But if you find no dead lice and the lice appear as active as before, you should talk with your health care provider about trying a different medication.

Do I need to get rid of all the nits?

In the past, experts thought of nit removal as an all-important step. What, they reasoned, was the point of removing live lice if you were just going to leave the eggs to hatch into another generation of the pests?

But not all nits pose a threat of re-infestation. For one thing, nits that are attached to hair more than one centimeter from the scalp are unlikely to hatch since they depend on warmth from the scalp to incubate them. Also, medications that kill adult lice kill most nits, so nits on a child who has been treated for lice probably won't hatch.

In 2002, the American Academy of Pediatrics (AAP) updated its lice policy to focus instead on the removal of lice, not nits, because only lice can cause an infestation. In fact, the AAP says that it is not necessary to remove nits at all once a person has been treated for lice. In its policy statement, the AAP also took a stand against the no-nit policies of many schools and childcare centers. Schools and childcare centers many times send children home immediately when a child has lice, and does not allow them to return until they are completely free of nits. The AAP argues that these policies are ineffective in controlling the spread of lice and do not reduce the incidence of lice infestations.

The reality today is, however, you may have to remove nits since many schools still exclude children who have them. While the AAP doesn't advocate nit removal, you and your child may simply be more comfortable getting rid of the nits as well.

How do I get rid of nits?

There are many remedies -- from commercial products to vinegar -- suggested for dissolving the "glue" that attaches the nit to the hair. You're welcome to try them, but the solution that works best is the most labor-intensive: removing the nits by hand.

Here are some suggestions for making the nit-picking task less daunting:

  • Lighten up. Bright sunlight is by far the best for your search; indoors, use a bright light such as a clip-on desk lamp that you can move close to your child's head.
  • Magnify the problem. Give your vision a boost with an inexpensive pair of magnifying reading glasses from your local drugstore; they'll double the effectiveness of your check.
  • Divide and conquer. Use hairclips to section hair and go through it strand by strand, sliding each nit off with your fingers or using nail scissors to cut the nit-bearing hair close to the scalp. Drop it in a bowl of water. Pour the water down the drain when you're done.
  • Use a good comb. Plastic lice combs are less effective than metal, but the tiniest-toothed flea-style combs are painful for all involved. The National Pediculosis Association (NPA) recently began selling a comb called the LiceMeister, designed according to the latest research. With rounded teeth nearly twice as long as other lice combs, it gets all the way through thick hair but doesn't pull as miserably. (You can order one from the NPA by calling 800-323-1305.)
  • Give nits the slip. Studies haven't proved that oils suffocate any leftover lice, but experts say there's little doubt that soaking the hair in olive oil, coconut oil, or an oil-based product makes it much easier to comb the nits out.
  • Nit-pick daily. Check for nits and lice daily until your child has passed an all-clear inspection. This may take up to two weeks.

Professional lice removal salons have recently been opening in several cities across the United States. If the thought of removing nits makes you squeamish, ask your childs pediatrician about lice removal salons.

What else can I do to get rid of lice?

Lice are almost always passed through direct head-to-head contact, so you needn't drive yourself crazy vacuuming every inch of your house. But a normal cleaning can't hurt since lice can survive 24 to 48 hours off the human head. (Head lice do not live on animals other than humans, so don't worry about dogs or cats carrying head lice.)

Vacuum each room thoroughly, and wash linens, towels, and clothes your child has recently worn in hot water (130 degrees Fahrenheit for 20 minutes). (Afterwards, return your water heater to 120 degrees; that's the safest way to prevent scalding-water burns in children.) An alternative to washing all your clothes and linens is simply to put them in a large, sealed plastic bag for 10 days; deprived of humans to feast on, the lice will die. Put all combs, brushes, and hair accessories in hot soapy water and let them soak overnight. Don't forget the car: Vacuum your child's seat and headrest. There's no need to use lice sprays; experts say they can expose your child to too much insecticide.

Be persistent, and beware of stopping treatment too soon. In lice-prone areas, it's common to hear parents say their child has been repeatedly re-infested. In many cases, however, the lice were not completely eradicated the first time around. Keep checking your child's head daily until you're sure the pests are gone; then check weekly to make sure your child hasn't picked up more unwanted pests. If your child continues to suffer from lice after repeated treatments, your pediatrician may give your child an oral medication to help eradicate them.

Further Resources

Pantell, Robert H. M.D., James F. Fries M.D., and Donald M. Vickery M.D. Taking Care of Your Child: A Parent's Illustrated Guide to Complete Medical Care, Eighth Edition. 2009. Da Capo Lifelong Books.

References

Massachusetts Department of Public Health, Virtual Hospital. Public Health Fact Sheet: Pediculosos. Updated June 2008. http://www.mass.gov/Eeohhs2/docs/dph/cdc/factsheets/eee.pdf

The National Pediculosis Association, http://www.headlice.org

Frankowski BL et al. Head Lice. Pediatrics. Volume 110, Number 3. September 2002. http://aappolicy.aappublications.org/cgi/content/full/pediatrics;110/3/638

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