Lotions and shampoos containing 1% permethrin (Nix) often work well. They can be bought at the store without a prescription. If these do not work, a doctor can give you a prescription for stronger medicine. Such medicine should be used exactly as directed.

To use the medicine shampoo, first rinse and dry the hair. Then apply the medicine to the hair and scalp. After 10 minutes, rinse it off. Check for lice and nits again in 1 week and repeat the treatment if necessary.

An important part of treatment is removing the eggs (nits). Certain products make the nits easier to remove. Some dishwashing detergents can help dissolve the "glue" that makes the nits stick to the hair shaft.

• You can remove the eggs with a nit comb. Before doing this, rub olive oil in the hair or run the metal comb through beeswax. This helps make the nits easier to remove.
• Metal combs with very fine teeth are stronger and more effective than plastic nit combs. These metal combs are easier to find in pet stores or on the Internet than in pharmacies.
• Removing eggs may prevent the lice from returning if the medication fails to kill every one of them.
• Treat children and adults with lice promptly and thoroughly.
• Wash all clothes and bed linens in hot water with detergent. This also helps prevent head lice from spreading to others during the short period when head lice can survive off the human body.
• Repeat combing for nits in 7-10 days.

Malathion 0.5% in isopropanol is FDA approved for the treatment of head lice. Apply it to dry hair until the hair and scalp are wet. Leave it on for 12 hours. Malathion may be useful for resistant infections.

Treatment can cause significant side effects in children younger than 6 months old, the elderly, and anyone weighing less than 110 lbs (50 kg), especially when the treatment is used repeatedly in a short period of time.

Lice are usually killed with proper treatment. However, lice may come back, especially if the source is not corrected. For example, a classroom with many infected children can cause kids to repeatedly get lice.

When one case is detected in a family or a school or child-care center, every child at that location should be examined for head lice. This can help prevent further spreading.

Some people will develop a secondary skin infection from scratching. Antihistamines can help relieve the itching. 

Call your health care provider if symptoms continue after home treatment, or if you develop areas of red, tender skin, which could mean a possible infection.