Lice 911

Photos and Symptoms of Head Lice

What do head lice look like?

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

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.
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: 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.

What are the symptoms of head lice?

• Tickling feeling of something moving in the hair.
• Itching, caused by an allergic reaction to the bites.
• Irritability.
• Sores on the head caused by scratching. These sores can sometimes become infected.

 

How is head lice diagnosed?

An infestation is diagnosed by looking closely through the hair and scalp for nits, nymphs, or adults. They can usually be found behind the ears, back of neck and part lines. It can be difficult to find a live bug. There are usually a few of them and they can move quickly. If crawling lice are not seen, finding nits within a 1/4 inch of the scalp strongly suggests that a person is infested and should be treated. If you only find nits more than 1/4 inch from the scalp (and don't see a nymph or adult louse), the infestation is probably an old one. If you are not sure if a person has head lice, the diagnosis should be made by your health care provider, school nurse, or a professional from the local health department.