Head Lice
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Head lice are parasitic insects found on the heads of people. They are also called Pediculus humanus capitis (peh-DICK-you-lus HUE-man-us CAP-ih-TUS). Having head lice is very common. There are no reliable data on how many people get head lice in the United States each year.
Who is at risk for getting head lice?
* Anyone who comes in close contact (especially head-to-head contact) with someone who already has head lice.
* Occasionally, head lice may be acquired from contact with clothing (such as hats, scarves, coats) or other personal items (such as brushes or towels) that belong to an infested person.
* Preschool and elementary-age children and their families are high risk.
* Girls get head lice more often than boys, women more than men.
* In the United States, African-Americans rarely get head lice.
Personal hygiene or cleanliness in the home or school has nothing to do with getting head lice.
What do head lice look like?
There are three forms of lice: the egg (also called a nit), the nymph, and the adult.
Nit
Nits are head lice eggs. They are very small, about the size of a knot in thread, hard to see, and are often confused for dandruff or hair spray droplets. Nits are laid by the adult female at the base of the hair shaft nearest the scalp. They are firmly attached to the hair shaft. They are oval and usually yellow to white. Nits take about 1 week to hatch. Eggs that are likely to hatch are usually located within ¼ inch of the scalp.
Nymph
The nit hatches into a baby louse called a nymph. It looks like an adult head louse, but smaller. Nymphs mature into adults about 7 days after hatching. To live, the nymph must feed on blood.
Adult
The adult louse is about the size of a sesame seed, has six legs, and is tan to grayish-white. In persons with dark hair, the adult louse will look darker. Adult lice can live up to 30 days on a person’s head. To live, adult lice need to feed on blood. If the louse falls off a person, it dies within 2 days.
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,
* Irritability, and
* Sores on the head caused by scratching.
Where are head lice most commonly found?
They are most commonly found on the scalp, behind the ears and near the neckline at the back of the neck. Head lice are rarely found on the body, eyelashes, or eyebrows.
How did my child get head lice?
• Contact with an infested person is the most common way to get head lice.
• Head-to-head contact is common during play at school and at home (sports activities, on a playground, slumber parties, at camp).
Less common ways to get head lice are:
• Wearing clothing, such as hats, scarves, coats, sports uniforms, or hair ribbons, recently worn by an infested person,
• Using infested combs, brushes, or towels, or
• Lying on a bed, couch, pillow, carpet, or stuffed animal that has recently been in contact with an infested person.
How is head lice infestation diagnosed?
• An infestation is diagnosed by looking closely through the hair and scalp for nits, nymphs, or adults.
• Finding a nymph or adult may be difficult; there are usually few of them and they can move quickly from searching fingers.
• If crawling lice are not seen, finding nits within a ¼ inch of the scalp confirms that a person is infested and should be treated.
• If you only find nits more than ¼ inch from the scalp (and don’t see a nymph or adult louse), the infestation is probably an old one and does not need to be treated.
• If you are not sure if a person has head lice, see your health care provider or school nurse.
For more information on Head Lice, visit:
Tulsa Health Department
(918) 595-4505
epidemiology@tulsa-health.org
Oklahoma State Department of Health
(405) 271-4060
www.health.state.ok.us/program/cdd/infec.html
Centers for Disease Control and Prevention
(888) 443-7232
www.cdc.gov
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