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Head Lice (Pediculosis)

What are head lice?

Head lice are tiny insects that feed on blood from the human scalp and lay their eggs on hair. Head lice are very common, particularly in children. There is no connection between head lice and the length of someone's hair or the cleanliness of the hair, body, or home or school environment.

The medical name for head lice is Pediculosis humanus capitis.

How do people get head lice?

The most common way to get head lice is head-to-head contact with a person who already has head lice. Head-to-head contact is common at home and school, in sports, on the playground, and at sleepovers and at camp.

It is very uncommon, but possible, to get head lice from clothing or belongings containing lice or nits that have crawled or fallen from a person with head lice. Examples include:

  • Recently worn or used hats, scarves, coats, sports uniforms or items such as hair ribbons, barrettes, combs, brushes, towels, and stuffed animals
  • Beds, sofas, pillows, or carpet. (The risk of getting head lice from a louse or nit that has fallen onto carpet or furniture is very small, however.)

Head lice cannot hop or jump, and they do not have wings, so they cannot fly.

You cannot catch head lice from dogs, cats, and other pets - head lice cannot survive on them.

Do head lice carry disease?

Head lice are not known to transmit any disease and therefore are not considered a health hazard. However, people with head lice sometimes develop bacterial infections from scratching the skin or scalp.

What are the symptoms?

The most common sign of head lice is itching, but most people do not develop itching until after head lice have been present for several weeks. Other possible symptoms are a tickling feeling of something moving in the hair and sores on the head caused by scratching. Irritability and difficulty sleeping may also be signs, since head lice are most active in the dark.

What do head lice look like?

It is usually easiest to find head lice on the scalp behind the ears, and near the neckline at the back of the neck. Occasionally, lice fall onto a person's eyebrows and eyelashes.

There are three stages in the lifecycle of head lice, and each stage looks different.

  • Nits - Each day, a female louse lays 3-6 eggs, called nits. Nits are oval-shaped and very small - about the size of a knot in thread. Firmly attached to the hair shaft, nits often appear yellow or white, although they can sometime appear to be the same color as a person's hair. Nits are hard to see, and people sometimes mistake dandruff, scabs, and hair spray droplets for nits. Nits are also hard to remove.
  • Nymph - Within 7-10 days, a nit hatches into a baby louse called a nymph. A nymph has six legs and is tan to grayish-white in color. Nymphs feed on blood and mature into adults in about 9-12 days.
  • Adult - The adult louse is about the size of a sesame seed, has six legs, and is tan to grayish-white in color. It may look darker in people with dark hair. Adult lice feed on blood from the scalp, and each adult can live about 30 days on a person's head. An adult louse will die within one or two days if it falls off the person.

Adult lice avoid light and can move quickly. They may be hard to see on the scalp. Parents may use a louse or nit comb to find eggs/nits.

Who is at risk for head lice?

In the United States, head lice are common among preschool children attending child care centers, elementary school children, and household members of children with head lice.

  • Girls get head lice more often than boys, and women more than men.
  • While it is possible for African-Americans to get head lice, they rarely do. This may be because the claws of the head louse found most frequently in the United States are better adapted for grasping the shape and width of some types of hair, but not others.

How do you treat (get rid of) head lice?

Many head lice medications are available over-the-counter. Your health care provider may prescribe others.

Shampoos, Crème Rinses, or Lice-killing lotions:

To treat for head lice using a shampoo, conditioner, or lice-killing hair lotion, follow these steps:

  • Before applying treatment, remove clothing that can become wet or stained during treatment.
  • Do not use hair conditioner or combination shampoo/conditioner before using lice medicine.
  • Apply lice medicine according to the label instructions. Pay close attention to how long the product should be on the scalp.
  • Put on clean clothing after treatment.
  • Do not re-wash hair for 1-2 days after treatment.
  • You may wish to comb dead lice and any remaining live lice out of the hair using a nit comb, which you can buy at your local drugstore. (A flea comb made for cats and dogs may work.)
  • After treatment, check the hair every 2-3 days and continue to use a nit comb to remove any nits or lice you see.
  • Use the lice medicine again in 7-10 days according to product instructions. Do not use sooner than 7 days after the first use, as this may cause scalp irritation or other harmful side effects.
  • Check the hair once or twice a week for 2-3 weeks after you think that all lice and nits are gone. This can help prevent being re-infested with lice.
  • Ask your heathcare provider about the need treat anyone who has shared a bed with the person who has head lice.

Lice combs:

Follow the instructions packaged with a lice comb, if you use one as the only lice treatment. Metal combs are often better at removing lice than plastic combs. The scalp of the person with lice may need daily 30 minute to 1 hour combing sessions for several days in order to remove all crawling lice and any nits/eggs that are ¼ inch or closer to the scalp.

Other treatments:

S.C. DHEC does not recommend for or against use of herbal or botanical treatments for head lice. School districts may opt to allow these treatments, and may opt to identify which products are acceptable for treatment in order for a child to return to school.

Home remedies, such as oils, shortening, vinegar, etc., do not consistently clear head lice infestations. These are not recommended.

Kerosene and gasoline should NEVER be used to treat head lice.

Are there any side effects from using chemical treatments for head lice?

According to the U.S. Centers for Disease Control and Prevention (CDC), chemical treatments for head lice are generally safe and effective when used correctly. Some treatments may cause an itching or a mild burning sensation caused by inflammation of the skin on the scalp. Most products used to treat head lice are pesticides that can be absorbed through the skin. Use any lice killing medicine only as directed.

Check with your health care provider if you have used a lice-killing product 2-3 times, following label directions, and there are still live crawling lice visible. Your health care provider may recommend a different treatment.

What can I do to stop the spread of head lice?

Take these steps to help prevent the spread of head lice to other members of your household:

  • Avoid head-to-head (hair-to-hair) contact during play and other activities at home, school, and elsewhere (sports activities, playground, slumber parties, and camp).
  • Do not share clothing such as hats, scarves, coats, sports uniforms, hair ribbons, or barrettes.
  • Do not share combs, brushes, or towels. Disinfect combs and brushes used by an infested person by soaking them in hot water (at least 130° F) for 5-10 minutes.
  • Do not lie on beds, couches, pillows, carpets, or stuffed animals that have recently been in contact with an infested person.
  • Machine-wash all washable clothing and bed linens touched by the person with head lice in the two days before treatment. Use the hot water cycle for washing and the high-heat dryer setting. Dry the laundry using the hot cycle for at least 20 minutes.
  • Dry clean clothing that is not washable (coats, hats, scarves, etc.)
  • Place clothing, stuffed animals, comforters, or other items that cannot be dry cleaned or washed into plastic bags. Seal the bags for two weeks.
  • Check the scalps of all household members of the person with lice. Treat anyone with live lice or eggs that appear to be ¼ inch or closer the scalp.

What are child care centers and schools supposed to do when a child has head lice?

Children will need to be treated for head lice if there are live, crawling lice seen on the scalp, or if there are nits/eggs that appear to be ¼ inch from the scalp. Children and students may remain at school until the end of the day. They should avoid activities that include head-to-head contact. Childcare centers may opt to send children home right away when lice are found, if head-to-head contact cannot be avoided in the classroom/center.

Children may return to school or childcare after one treatment with an over-the-counter or prescription lice-killing product. The school may make recommendations for products. The school or center may also allow children to return after crawling lice-nits have been removed from the hair by combing or heat treatment methods.

The child cannot return to school if there are any live, crawling lice seen on the scalp. Check the child’s scalp 7-10 days after first treatment. If there are any live crawling lice, the treatment must be repeated in order to return to school.

References and Additional Information

www.cdc.gov/parasites/lice/head/index.html

Head Lice Smart (DHEC) (pdf)

School Exclusion List (DHEC)

“Look for Head Lice” (poster for children)

“Head Lice” American Academy of Pediatrics Policy