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Lice Facts and Pictures

From the National Pediculosis Association

Center for Disease Control and Prevention (CDC)

  • Nits (the eggs of the head louse) are small brownish, oval-shaped eggs that are "to the side of a hair shaft glued" at an angle.

  • Nits must be laid by live lice. You cannot "catch nits."

  • Once laid, it takes 7-10 days for a nit to hatch, and another 7-10 days for the female to mature and begin laying her own eggs.

  • Head lice are clear in color when hatched, then quickly develop a reddish-brown color after feeding.

  • Head lice are about the size of sesame seeds.

  • Head lice have six legs equipped with claws to grasp the hair.

  • Head lice are crawling insects. They cannot hop, jump, or fly.

  • Head lice do not thrive on pets.

  • 3% of the kids at most schools have lice at any given time

  • Head lice are small, wingless insects which feed on human blood. They need human blood in order to survive.

  • Head lice live for approximately 30-35 days on a host and a female louse may lay up to 100 nits (eggs).

  • Head lice off of their human hosts will starve. The NPA suggests that, in most cases, a head louse will not survive for more than 24 hours off of its human host. 

Home Cleaning Procedures:

Each time a person is treated for Head Lice, household (fabric) furniture items, carpet, clothing, and hair accessories must also be treated. Lice are parasites that require human blood to survive. They can only live 24-48 hours away from a human host.

Clothing, Bedding, Stuffed Animals, and Backpacks: Wash with warm water, or put them in the dryer for 30-60 minutes on high heat, or avoid making contact for 48 hours, or use the Magic Nit Pick Household Spray (allow 15-20min), and you're good to go!

Combs and Hair Accessories: Put in bucket for water and add small amount of bleach for 4+ hours or put in plastic bag and freeze for 4+hours. 

Car Seats/Furniture: Vacuum, or cover with cloth/sheet for 2 days, or spray the Magic Nit Pick Household Spray (allow 15-20min), and you're good to go!

Carpet: Vacuum

Note: The safest method to clean something is to simply separate from it for 2-3 days. (either in a plastic bag or put in an unused closet. )

What are head lice?

The head louse, or Pediculus humans capitis (peh-DICK-you-lus HUE-man-us CAP-ih-TUS), is a parasitic insect that can be found on the head, eyebrows, and eyelashes of people. Head lice feed on human blood several time a day and live close to the human scalp. Head lice are not known to spread disease.

Head Lice Picture

Egg (Nit), Louse, Lice

Who is at risk for getting head lice?

Head lice are found worldwide. In the United States, infestation with head lice is most common among preschool children attending child care, elementary school children, and the household members of infested children. Although reliable data on how many people in the United States get head lice each year are not available, an estimated 6 million to 12 million infestations occur each year in the United States among children 3 to 11 years of age. In the United States, infestation with head lice is much less common among African-Americans than among persons of other races, possibly because the claws of the of the head louse found most frequently in the United States are better adapted for grasping the shape and width of the hair shaft of other races.

Head lice move by crawling; they cannot hop or fly. Head lice are spread by direct contact with the hair of an infested person. Anyone who comes in head-to-head contact with someone who already has head lice is at greatest risk. 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 is uncommon. 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 (also called a nit), the nymph, and the adult.

Head Lice

Life Cycle of The Head Lice

Head Lice/Egg/Nit: Nits are lice eggs laid by the adult female head louse 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. Nits are often confused with dandruff, scabs, or hair spray droplets. Head lice nits usually take about 8-9 days to hatch. Eggs that are likely to hatch are usually located no more than ¼ inch (or 1 centimeter) from the base of the hair shaft.

Head Lice

Lice Egg (Nit)

Head Lice/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.

Adult head louse

Had Lice

Nymph (Young Louse)

Head Lice/Adult louse: 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. Adult head lice may look darker in persons with dark hair than in persons with light hair. 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.

Head Lice

Adult Lice

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. Head lice hold tightly to hair with hook-like claws at the end of each of their six legs; head lice nits are cemented firmly to the hair shaft and can be difficult to remove.

What are the signs and symptoms of head lice infestation?

  • 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. These sores can sometimes become infected with bacteria found on the person's skin.

How can your 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).

  • Uncommonly, head lice may be spread by sharing clothing or belongings onto which lice or nits may have crawled or fallen. Examples include:

  • Sharing clothing (hats, scarves, coats, sports uniforms) or articles (hair ribbons, barrettes, combs, brushes, towels, stuffed animals) recently worn or used by an infested person;

  • Lying on a bed, couch, pillow, or carpet that has recently been in contact with an infested person. The risk of getting an infestation by a louse or nit that has fallen onto a carpet or furniture is very small.

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. Because nymphs and adult lice are very small, move quickly, and avoid light, they can be difficult to find. Use of a magnifying lens and a fine-toothed comb may be helpful to find live lice. If crawling lice are not seen, finding nits firmly attached within a 1/4 inch of base of the hair shafts strongly suggests, but does not confirm, that a person is infested and should be treated. Nits that are attached more than 1/4 inch from the base of the hair shaft are almost always dead or already hatched. Nits are often confused with other things found in the hair such as dandruff, hair spray droplets, and dirt particles. If no live nymphs or adult lice are seen, and the only nits found are more than ¼-inch from the scalp, the infestation is probably old and no longer active and does not need to be treated.

Should you call you call a doctor?

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. 

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