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Each year millions of school-aged children in the United States get head lice. Though head lice may be a nuisance, they don't cause serious illness or carry any diseases. Also, head lice can be treated at home.

The following information from the American Academy of Pediatrics (AAP) will help you check for, treat, and prevent the spread of head lice.

What are head lice?

Head lice are tiny insects. They are about the size of a sesame seed (2–3 mm long). Their bodies are usually pale and gray, but color may vary. One "lice" is called a louse.

Head lice feed on tiny amounts of blood from the scalp. They usually survive less than a day if not on a person's scalp. Lice lay and attach their eggs to hair close to the scalp.

The eggs and their shell casings are called nits. They are oval (about 0.8 x 0.3 mm) and usually yellow to white. Nits are attached with a sticky substance that holds them firmly in place. After the eggs hatch, the empty nits remain attached to the hair shaft.

Head lice live about 28 days. They can multiply quickly, laying up to 10 eggs a day. It only takes about 12 days for newly hatched eggs to reach adulthood. This cycle can repeat itself every 3 weeks if head lice are left untreated.

Who gets head lice?

Anyone can get head lice. Head lice are most common in preschool- and elementary school–aged children. It doesn't matter how clean your hair or home may be. It doesn't matter where children and families live, play, or work.

How are head lice spread?

Head lice are crawling insects. They cannot jump, hop, or fly. The main way head lice spread is from close, prolonged head-to-head contact. There is a very small chance that head lice will spread because of sharing items such as combs, brushes, and hats.

What are symptoms of head lice?

The most common symptom of head lice is itching. It may take up to 4 weeks after lice get on the scalp for the itching to begin. Most of the itching happens behind the ears or at the back of the neck. Also, itching caused by head lice can last for weeks, even after the lice are gone. However, an itchy scalp also may be caused by eczema, dandruff, or an allergy to hair products.

How do you check for head lice?

Regular checks for head lice are a good way to spot head lice before they have time to multiply and infest your child's head.
  • Seat your child in a brightly lit room.
  • Part the hair and look at your child's scalp.
  • Look for crawling lice and for nits.
    • Live lice are hard to find. They avoid light and move quickly.
    • Nits will look like small white or yellow-brown specks and be firmly attached to the hair near the scalp. The easiest place to find them is at the hairline at the back of the neck or behind the ears. Nits can be confused with many other things, such as dandruff, dirt particles, or hair spray droplets. The way to tell the difference is that nits are attached while dandruff, dirt, or other particles are not.
  • Wet the hair. Use a fine-toothed comb to help comb out the lice or nits. Comb through your child's hair in small sections. After each comb-through, wipe the comb on a wet paper towel. Examine the scalp, comb, and paper towel carefully.

How do you treat head lice?

Check with your child's doctor first before beginning any head lice treatment. The most effective way to treat head lice is with head lice medicine. Head lice medicine should only be used when it is certain that your child has head lice.

When head lice medicines are used, it is important to use them safely. Here are some safety guidelines.

  • Follow the directions on the package.
  • Never let children apply the medicine. Medicine should be applied by an adult.
  • Check with your child's doctor before beginning a second or third treatment. A second treatment is usually needed 10 days after the first treatment. In some cases a third treatment 10 days after the second treatment is needed.
  • Do not use medicine on a child 2 years or younger without first checking with your child's doctor.
  • Do not use or apply medicine to children if you are pregnant or nursing without first checking with your doctor.
  • Store medicine in a locked cabinet, out of sight and reach of children.
  • Ask your child's doctor if you have any questions.

Note: The comb-out method (removing head lice without medicine from damp hair with a fine-toothed comb) often fails. Also, home remedies, like using petroleum jelly, mayonnaise, tub margarine, herbal oils, or olive oil, have not been scientifically proven to work. Never use dangerous products like gasoline or kerosene or medicines made for use on animals!

What head lice medicines are available?

Here is a list of head lice medicines approved by the US Food and Drug Administration. Check with your child's doctor before beginning any treatment.

Head Lice Medicines​ ​
​Treatment ​Description
Permethrin cream (1%)​ ​Available without a prescription
Applied to shampooed and towel dried hair, then rinsed off after 10 minutes
Approved for use in children 2 months and older
​Pyrethrin-based product (shampoo or hair mousse) ​Available without a prescription
Applied to dry hair and rinsed off after 10 minutes
Should not be used in people who are allergic to chrysanthemums
Malathion lotion (0.5%)​ ​Prescription needed
Applied to dry hair and rinsed off after 8 to 12 hours
Approved for use in children 6 years or older
Flammable; may cause chemical burns
​Benzyl alcohol lotion (0.5%) ​Prescription needed.
Applied to dry hair and rinsed off after 10 minutes. Repeat in 7 days.
Contains no neurotoxic pesticide.
Approved for use in children 6 months and older. Not recommended for infants younger than 6 months.
Spinosad topical suspension (9%)​ ​Prescription needed.
Applied to dry hair and rinsed off after 10 minutes.
Approved for use in children 4 years and older. Not recommended for infants younger than 6 months.
Made from a naturally occurring soil bacterium that causes lice to become paralyzed and then die. Also contains benzyl alcohol.
​Ivermectin lotion (0.5%) ​Prescription needed.
Applied to dry hair and rinsed off after 10 minutes.
Approved as a one-time-use, topical treatment of head lice in children 6 months and older. If there is leftover medicine, it needs to be thrown out, not reused.
Lindane shampoo (1%)​ ​Prescription needed
No longer recommended by most experts
 

What else do I need to know about treating head lice?

You do not need to throw away any items belonging to your child. However, you may want to wash your child's clothes, towels, hats, and bed linens in hot water and dry on high heat if they were used within 3 days before head lice were found and treated. Items that cannot be washed may be dry-cleaned or sealed in a plastic bag for 2 weeks.

Do not spray pesticides in your home; they can expose your family to dangerous chemicals and are not necessary when you treat your child's scalp and hair properly.

If your child has head lice, all household members and close contacts should also be checked and treated if necessary.

About "no-nit" policies

Some schools have "no-nit" policies stating that students who still have nits in their hair cannot return to school. The AAP and the National Association of School Nurses discourage such policies and believe a child should not miss school because of head lice.

Remember

Head lice don't put your child at risk for any serious health problems. If your child has head lice, work quickly to treat your child to prevent the head lice from spreading.

Additional Information

 

Last Updated
7/31/2014
Source
Head Lice (Copyright © 2010 American Academy of Pediatrics, Updated 08/2013)
The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.