Anthony L. Komaroff, M.D.
— DEAR DOCTOR K: My daughter was sent home from school with head lice. I'm embarrassed and worried. What should I do?
DEAR READER: Don't be embarrassed. Head lice are not caused by poor hygiene or housekeeping. They simply are out there in the environment, like termites, which can affect even the cleanest homes.
Head lice are small insects that infest the hair on people's heads. When they bite the skin to feed on a person's blood, their saliva gets into the bite. The person's immune system reacts against the foreign saliva. This causes a lot of itching.
A single insect is called a louse. A louse can lay more than 100 eggs, called nits. Nits attach tightly to the hair, usually close to the scalp. They are little oval capsules, colored white or tan.
A person who has an active infection with head lice normally has fewer than a dozen live lice on his or her head at a time. However, hundreds of nits may be present. You remove nits with a comb, as described below, and lice with insecticide medicines.
First, add a hair conditioner to your daughter's hair, wash it out and lightly dry the hair. Then brush it out to remove any tangles. Next, use a comb with very fine teeth. Draw the comb in a series of continuous strokes through the hair. At the end of each stroke, examine the comb for nits and wash it. You may need to do this several times weekly until no lice are seen for two or more weeks.
You should treat your daughter with insecticides only if she has live (crawling) head lice. Do not treat if you've seen only nits. The insecticides used for lice (called pediculicides) are available over-the-counter in drugstores. Most pediculicides are applied as a shampoo, then washed off 10 minutes later. A second treatment is often necessary, about 10 days later.
These products work very well for most people, but some head lice are resistant to them. If live head lice are discovered a day after treatment, ask your doctor about pediculicides that are available by prescription. The most commonly used pediculicide is permethrin.
Do not use products that are not registered by the FDA as pediculicides.
It's a good idea to launder or change items (like clothes, towels or bed linens) that were in direct contact with your daughter's hair during the last day or so. Washing items in hot water or drying them in high heat will kill lice and nits.
Also, inspect everyone else living in your home for head lice.
Fortunately, head lice are less common today than they were years ago. They don't carry diseases, they don't jump to our pets (and then back to us), and they are easy to get rid of. Some people are embarrassed if they or a member of their family has head lice. They shouldn't be: Head lice can affect anyone.
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.
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