Head Lice

Frequently Asked Questions:

What are head lice?

The head louse is a parasitic insect that can be found on the head, eyebrows, and eyelashes of people. Head lice feed on human blood several times a day and live close to the human scalp. 

Who is at risk for getting head lice?

Head lice is most common among pre-school children attending child care, elementary schoolchildren, and the household members of infested children.  In the United States, infestation with head lice is much less common among African-Americans than among persons of other races.  Anyone who comes in head-to-head contact with someone who already has head lice is at greatest risk. 

How is head lice spread?

Head lice move by crawling; they cannot hop or fly. Head lice are spread by direct contact with the hair of an infested person. Generally head lice is NOT spread by contact with clothing (such as hats, scarves, coats) or other personal items (such as combs, brushes, or towels) used by an infested person, but is possible. Personal hygiene or cleanliness in the home or school has nothing to do with getting head lice.

What do head lice look like?

Head lice have three forms: the egg (nit), the nymph, and the adult.

Actual size of the three lice forms compared to a penny. (CDC Photo)


Nits are lice eggs laid by the adult female head lice at the base of the hair shaft nearest the scalp. Nits are firmly attached to the hair shaft and are oval-shaped and very small (about the size of a knot in thread) and hard to see. Nits often appear yellow or white although live nits sometimes appear to be the same color as the hair of the infested person. 

Illustration of egg on a hair shaft. (CDC Photo)

Nymph: A nymph is an immature louse that hatches from the nit. A nymph looks like an adult head louse, but is smaller. To live, a nymph must feed on blood. Nymphs mature into adults about 9–12 days after hatching from the nit.

Nymph form. (cdc photo)

Adult: The fully grown and developed adult louse is about the size of a sesame seed, has six legs, and is tan to grayish-white in color.  To survive, adult head lice must feed on blood. An adult head louse can live about 30 days on a person's head but will die within one or two days if it falls off a person. Adult female head lice are usually larger than males and can lay about six eggs each day.

Adult louse. (cdc photo)

Where are head lice most commonly found?

Head lice and head lice nits are found almost exclusively on the scalp, particularly around and behind the ears and near the neckline at the back of the head. Head lice or head lice nits sometimes are found on the eyelashes or eyebrows but this is uncommon. 

What are the signs and symptoms of head lice infestation?

  • Tickling feeling of something moving in the hair.
  • Itching, caused by an allergic reaction to the bites of the head louse.
  • Irritability and difficulty sleeping; head lice are most active in the dark.
  • Sores on the head caused by scratching. 

How did my child get head lice?

Head-to-head contact with an already infested person is the most common way to get head lice. Head-to-head contact is common during play at school, at home, and elsewhere (sports activities, playground, slumber parties, camp).

Although uncommon, head lice can be spread by sharing clothing or belongings. This happens when lice crawl, or nits attached to shed hair hatch, and get on the shared clothing or belongings.

How is head lice infestation diagnosed?

The diagnosis of a head lice infestation is best made by finding a live nymph or adult louse on the scalp or hair of a person. If crawling lice are not seen, finding nits firmly attached to hair strongly suggests, but does not confirm, that a person is infested and should be treated. 

If you are not sure if a person has head lice, the diagnosis should be made by their health care provider, local health department, or other person trained to identify live head lice.

Can head lice be spread by sharing sports helmets or headphones?

Head lice are spread most commonly by direct contact with the hair of an infested person. Spread by contact with inanimate objects and personal belongings may occur but is very uncommon. 

Can wigs or hair pieces spread lice?

Head lice and their eggs (nits) soon perish if separated from their human host. Adult head lice can live only a day or so off the human head without blood for feeding. Nymphs (young head lice) can live only for several hours without feeding on a human. Nits (head lice eggs) generally die within a week away from their human host and cannot hatch at a temperature lower than that close to the human scalp. For these reasons, the risk of transmission of head lice from a wig or other hairpiece is extremely small, particularly if the wig or hairpiece has not been worn within the preceding 48 hours by someone who is actively infested with live head lice.

Can swimming spread lice?

Data show that head lice can survive under water for several hours but are unlikely to be spread by the water in a swimming pool. Head lice have been seen to hold tightly to human hair and not let go when submerged under water. 

Swimming or washing the hair within 1–2 days after treatment with some head lice medicines might make some treatments less effective. Seek the advice of your health care provider or health department if you have questions.

How is head lice infestation treated?

Treatment for head lice is recommended for persons diagnosed with an active infestation. 

Personal possessions such as: hats, scarves, pillow cases, bedding, clothing, and towels worn or used by the infested person in the 2-day period just before treatment needs to be machine washed and dried using the hot water and hot air cycles because lice and eggs are killed by exposure for 5 minutes to temperatures greater than 53.5°C (128.3°F). Items that cannot be laundered may be dry-cleaned or sealed in a plastic bag for two weeks. 

Items such as hats, grooming aids, and towels that come in contact with the hair of an infested person should not be shared. 

Vacuuming furniture and floors can remove an infested person's hairs that might have viable nits attached.

Treat the infested person(s): Requires using an Over-the-counter (OTC) or prescription medication. Follow these treatment steps:

  1. Before applying treatment, it may be helpful to remove clothing that can become wet or stained during treatment.
  2. Apply lice medicine, also called pediculicide, according to the instructions contained in the box or printed on the label. If the infested person has very long hair (longer than shoulder length), it may be necessary to use a second bottle. Pay special attention to instructions on the label or in the box regarding how long the medication should be left on the hair and how it should be washed out.

    WARNING:  Do not use a combination shampoo/conditioner, or conditioner before using lice medicine. Do not re–wash the hair for 1–2 days after the lice medicine is removed.

  • Have the infested person put on clean clothing after treatment.
  • If a few live lice are still found 8–12 hours after treatment, but are moving more slowly than before, do not retreat. The medicine may take longer to kill all the lice. Comb dead and any remaining live lice out of the hair using a fine–toothed nit comb.
  • If, after 8–12 hours of treatment, no dead lice are found and lice seem as active as before, the medicine may not be working. Do not retreat until speaking with your health care provider.  If your health care provider recommends a different medication, carefully follow the treatment instructions contained in the box or printed on the label.
  • Nit (head lice egg) combs, often found in lice medicine packages, should be used to comb nits and lice from the hair shaft. 
  • After each treatment, checking the hair and combing with a nit comb to remove nits and lice every 2–3 days may decrease the chance of self–reinfestation. Continue to check for 2–3 weeks to be sure all lice and nits are gone. 
  • Retreatment is meant to kill any surviving hatched lice before they produce new eggs. For some drugs, retreatment is recommended routinely about a week after the first treatment (7–9 days, depending on the drug) and for others only if crawling lice are seen during this period. 
  • Supplemental Measures: Head lice do not survive long if they fall off a person and cannot feed. You don't need to spend a lot of time or money on housecleaning activities. Follow these steps to help avoid re–infestation by lice that have recently fallen off the hair or crawled onto clothing or furniture.

When treating head lice

  1. Machine wash and dry clothing, bed linens, and other items that the infested person wore or used during the 2 days before treatment using the hot water (130°F) laundry cycle and the high heat drying cycle. Clothing and items that are not washable can be dry–cleaned


sealed in a plastic bag and stored for 2 weeks.

  1. Soak combs and brushes in hot water (at least 130°F) for 5–10 minutes.
  2. Vacuum the floor and furniture, particularly where the infested person sat or lay. 
  3. Do not use fumigant sprays; they can be toxic if inhaled or absorbed through the skin.

Prevent Reinfestation:

  1. Do not use extra amounts of any lice medication unless instructed to do so by your physician and pharmacist. The drugs used to treat lice are insecticides and can be dangerous if they are misused or overused.
  2. All the medications listed above should be kept out of the eyes. If they get onto the eyes, they should be immediately flushed away.
  3. Do not treat an infested person more than 2–3 times with the same medication if it does not seem to be working. This may be caused by using the medicine incorrectly or by resistance to the medicine. Always seek the advice of your health care provider if this should happen. 
  4. Do not use different head lice drugs at the same time unless instructed to do so by your physician and pharmacist.

Is infestation with head lice reportable to health departments?

Most health departments do not require reporting of head lice infestation. However, it may be beneficial for the sake of others to share information with school nurses, parents of classmates, and others about contact with head lice.

Do head lice spread disease?

Head lice should not be considered as a medical or public health hazard. Head lice are not known to spread disease. 

The above information was provided by the Center for Disease Control and Prevention (CDC) for more information please click here to be directed to their website.