Head Lice

What are head lice?

Head lice are tiny wingless insects. They are less than 1/8 inch long (2 to 3 millimeters), or about the size of a sesame seed.

Head lice live in the hair and bite the scalp to suck blood. They attach their eggs, called nits, to the hair. The eggs then hatch after several days, producing more lice. Lice are not dangerous and don’t spread disease.

It is very common for schoolchildren to have head lice.

How do people get head lice?

You can get lice by coming into contact with living lice or their eggs. For example, sharing personal items such as a comb or hat is a way you can get lice. Lice may crawl or fall onto clothing, bedding, towels, or furniture, as well as combs and brushes. Head lice can live up to 3 days on such items.

What are the symptoms?

Itching is the most common symptom. Sometimes, however, there are no symptoms, especially at first, when there are just a few lice and nits.

Sometimes you may see the lice or nits. The nits look like tiny white dots attached firmly to a hair. They look like dandruff. Dandruff, however, is easily brushed out of the hair. Nits cannot be brushed or flicked off. They must be pulled off the hair with your fingers.

How is it diagnosed?

Your healthcare provider looks for lice or nits in your hair.

How is it treated?

Lice will not go away without proper treatment. Nonprescription anti-lice products, such as Nix rinse or RID shampoo, can be used to kill lice.

Use the anti-lice rinse or shampoo according to the instructions on the package or your healthcare provider's directions. Your provider will probably recommend that you repeat the treatment in 1 week because the nonprescription products kill only crawling lice. They don’t kill unhatched nits. So a second treatment in 7 to 10 days after the first may be needed to kill newly hatched lice.

If a nonprescription product does not kill the lice, you may need a shampoo prescribed by your healthcare provider. Prescription shampoos contain either malathion or lindane to kill the lice. These medicines may have side effects. It is usually better to try one of the safer, nonprescription products first.

• Malathion can sting if your skin is irritated from scratching. It is also flammable, so it is very important to stay away from heat sources or flames for the 8 to 12 hours after you apply it. Don’t use a hair dryer to dry the hair during this time. Let the hair dry naturally.
• Lindane is rarely prescribed because it can cause seizures if it is not used correctly. Also, lindane is not as effective as it used to be because lice are getting resistant to it. Lindane should never be used by small children or women who are pregnant or breastfeeding. Carefully follow your healthcare provider’s directions for its use. Don’t overuse it.

If you are pregnant or breastfeeding, check with your healthcare provider before you use any type of anti-lice product.

After treatment with antilice medicine, the nits will still be on your hair. You must remove all of the nits. Use a fine-tooth comb, tweezers, or your fingers to remove the nits. It’s important to do this for 2 reasons:

• The anti-lice medicine may not kill all the nits (eggs).
• A week later, if you didn’t remove the nits at the time of treatment and you see nits in the hair, you won’t know if they are new nits laid by lice that weren’t killed by the medicine. If they are new nits, the treatment was not effective and needs to be repeated. Because the treatment can have side effects, especially in small children, it is very important to know if the first treatment worked so you can avoid repeating it unnecessarily.

Check everyone else living in your home and treat them if they have lice. Ask your healthcare provider to recommend the best treatment based on their ages and whether they are pregnant. Clean all items that have come into contact with the head and hair. Clean combs and brushes well by soaking them in a disinfectant such as Lysol. Hats, scarves, towels, and bed sheets should be washed in hot water and dried in a hot drier. Contaminated clothing that cannot be washed or dry cleaned should be sealed in a plastic bag for 2 weeks to make sure you have killed all of the lice. (The lice can live for only a few days off the body.) Sometimes people are advised to buy a special lice insecticide spray to use on furniture. However, careful vacuuming may be as effective in most cases. Pets don’t need to be treated.

What can be done to help prevent lice?

To help prevent lice, don’t share personal items such as combs, brushes, hats, scarves, and towels.

Lice can be very hard to prevent among small children who nap together and share hats and cuddly toys. Because it is so hard to prevent the spread of lice among preschool and school-age children, lice should not be seen as a sign of poor hygiene or failure by parents. Rather, the problem should just be dealt with in a calm, practical manner.