Dear Doctor Column, November 22, 2004

Head Lice Can Be Treated With Over-the-counter Medicine

Question:

My child has had head lice three times so far this year since school began in August. Should I use something stronger to treat my son?

Answer:

You may need to but you should contact his pediatrician first. Lice are tiny but visible insects that live on humans and animals, primarily on the hairy parts of the body. They bite and suck blood from the skin, causing intense itching. Preschool and elementary-age children, 3-10, and their families are infested most often. Girls get head lice more often than boys, women more than men. In the United States, African-Americans rarely get head lice. Head lice hold on to hair with hook-like claws found at the end of each of their six legs. Head lice are rarely found on the body, eyelashes, or eyebrows.

Recently, the Centers for Disease Control and Prevention issued a report on head lice, stating that the parasites may be developing resistance to traditional, commonly used treatments. Over-the-counter treatments do not seem to work as well as they used to, say health experts, but they are usually effective if parents will follow the directions explicitly. If at-home treatments do not work, parents should contact their pediatrician, they add. Stronger, more toxic chemicals have been shown to have adverse side effects, so they are used only as a last resort.

Having head lice does not mean a child is dirty. As in your son's case, the problem often surfaces when children return to school in the fall as lice are easily passed from child to child during play activities or through sharing personal items. Additionally, you do not get head lice from pets, grass, trees, or dirt; head lice do not jump like fleas and do not fly. You can only get them from direct physical contact with another person or from something a person has recently used. Most children get them by sharing objects, such as combs, hats, scarves, stereo headsets, or athletic gear, with a person infested with the organisms. Other common sources are clothing, bedding, pillows, furniture, or towels recently used by an infested person.

A head louse lives about a month and feeds on human blood, which it cannot survive without for more than 48 hours. It attaches its eggs, called nits, which require body heat to hatch, to the hairs in the scalp. The nits hatch in 8 to 10 days, and the louse begins reproducing in 3 weeks.

Here are some suggestions for dealing with head lice:

• Examine each household member for head lice. Look at the back of the head and behind the ears. Using a good light, look closely near the bases of hairs for white oval egg cases (nits), which, although tiny, can be seen without a magnifying lens. Often there are clusters of eggs that cannot be easily removed because they are firmly attached to hairs.
• Ask your pediatrician or pharmacist to recommend one of the many over-the-counter shampoos or rinses available to treat head lice. Shampooing with ordinary soap or shampoo will not kill lice. In general, a rinse or shampoo that contains 1% permethrin, such as Nix or Rid, is the drug of choice for treating head lice in adults and in children age 2 years and older. Read the directions and warnings on the label carefully before using any product.
• Comb the hair thoroughly with a fine-tooth comb after you have used the appropriate shampoo or rinse. The comb usually comes with the shampoos. Start close to the scalp to dislodge nits at the base of hairs. It may be necessary to use a hard brush or tweezers to remove nits, but you do not need to cut the child's hair.
• You may not be able to remove all nits. Although most eggs left after treatment will not hatch, many of the over-the-counter products recommend a second course of treatment a week to 10 days after the first treatment to ensure any lice that have hatched since the first treatment are killed.

Once a child and other affected household members have been treated, these guidelines can help prevent reinfestation:

• Machine wash all washable clothing, bed linens, towels, and washcloths with hot water and detergent that your child has used in the past 3 days.
• Dry clean items of clothing that are not washable or seal them in a plastic bag for 10 days, during which time all the lice and nits will die.
• Soak combs and brushes for an hour in disinfectant, such as Lysol.
• Spray furniture with lice control sprays, which are available at most drug stores. Follow instructions carefully. Careful, thorough vacuuming may be as effective.
• Tell your child not to share or borrow caps, helmets, clothing, combs, brushes, or any other personal items at school.

Since your child has continued to have problems, call his pediatrician, who as we mentioned, may suggest a series of treatments with prescription medication that contains lindane.