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Head Lice Infestation (Pediculosis)
Head Lice Infestation
(Pediculosis)
What are head lice?
Head lice are insect parasites that are found on the heads of people. Infection with head lice is called pediculosis.
(The head louse, Pediculus humanus capitis, is different from the lice that cause body and pubic hair infections).
How common is head lice infestation?
Head lice infection is very common. It has been estimated that up to 12 million people acquire head lice every year.
Who is at risk for getting head lice?
Anyone who comes in close contact with someone who already has head lice, or their contaminated clothing and other belongings is at risk for acquiring head lice. Preschool and elementary school children (age 3-10 years) and their families are infected most often. Girls contract head lice more often than boys; women more often than men. African-Americans rarely acquire head lice.
How in the world does a child get head lice?
A child can contract head lice in a number of ways: - Contact with an already infested person. Personal contact is common during play, school, or sports activities, and at school, home, slumber parties, or camp;
- Wearing infested clothing, such as hats, scarves, coats, sports uniforms, or hair ribbons;
- Using infested combs, brushes, or towels; or
- Lying on a bed, couch, pillow, carpet, or stuffed animal that has recently been in contact with a person with lice.
What do head lice look like?
There are three forms of lice, namely the nit, the nymph, and the adult:
Nit: Nits are lice eggs. Nits are hard to see and are often confused with dandruff or hair spray droplets. Nits are found firmly attached to the hair shaft. They are oval and usually yellow to white. Nits take about a week to hatch.
Nymph: The nit hatches into a baby louse called a nymph. It looks like an adult head louse, but is 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 6 legs, and is tan to grayish-white in color. In persons with dark hair, the adult louse looks darker. Females lay nits; they are usually larger than males. 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.
Where are head lice most commonly found?
Head lice are most frequently located on the scalp behind the ears and near the neckline at the back of the neck. Head lice hold on to hair with hook-like claws that are found at the end of each of their six legs. Head lice are rarely found on the body, eyelashes, or eyebrows.
What are the signs and symptoms of head lice infestation?
The signs and symptoms are: - A tickling feeling of something moving in the hair;
- Itching (caused by the an allergic reaction to the bites);
- Sores on the head (caused by scratching);
- These sores on the head can sometimes become infected; and
- Irritability (a very nonspecific thing, to be sure).
How is a head lice infestation diagnosed?
Head lice can be detected by looking closely through the hair and scalp for nits, nymphs, or adults. Locating a nymph or adult may be difficult; there are usually only a few of them and they can move quickly from searching fingers. However, the presence of nits close to the scalp confirms that a person is infested. If the nits are located more than 1/4 inch from the scalp, the infestation is probably an old one. If you are not sure whether or not a person has head lice, the diagnosis should be made by a health care provider, school nurse, or a professional from the local health department or agricultural extension service. The nits of head lice are easily visible with a microscope.
How is a head lice infestation (pediculosis) treated?
For effective elimination of head lice, the infested individual, family members that are also infested, and the home must all be treated.
Treatment of the individual and the infected family members:
Over-the-counter (OTC) or prescription medications are used to treat the affected persons and their families. Follow these treatment steps: - Remove all clothing.
- Apply lice medicine, also called pediculicide, according to the label instructions. If your child has extra long hair, you may need to use a second bottle. WARNING: Do not use a creme rinse or combination shampoo/conditioner before using lice medicine. Do not re-wash hair for 1-2 days after treatment.
- Have the infested person put on clean clothing after treatment.
- If some live lice are still found 8-12 hours after treatment, but are moving more slowly than before, do not retreat. Comb dead and remaining live lice out of the hair. The medicine sometimes takes longer to kill the lice.
- If, 8-12 hours after treatment, no dead lice are found and lice seem as active as before, the medicine may not be working. See your health care provider for a different medication and follow their treatment instructions.
- Nit (head lice egg) combs, often found in lice medicine packages should be used to remove nits and lice from the hair shaft. Many flea combs made for cats and dogs are also effective.
- After the initial treatment, check, comb, and remove nits and lice from hair every 2-3 days.
- Re-treat in 7-10 days.
- Check all treated persons for 2- 3 weeks until you are sure all lice and nits are gone.
Treating the house:
Treating the whole house is a laborious but important task. Follow these steps: - Machine wash all washable clothing and bed linens that the infested person touched during the 2 days before treatment (to kill the lice and nits). Use the hot water cycle (130 degrees F; 55 degrees C) to wash clothes. Dry laundry using the hot cycle for at least 20 minutes.
- Dry clean clothing that is not washable, (coats, hats, scarves, etc.) OR Store all clothing, stuffed animals, comforters, etc., that cannot be washed or dry cleaned into a plastic bag and seal for 2 weeks.
- Soak combs and brushes for 1 hour in rubbing alcohol, LYSOL, or wash with soap and hot (130 degrees F; 55 degrees C) water.
- Vacuum the floor and furniture. Do not use fumigant sprays. (They can be toxic if inhaled.)
My child has head lice. I don't. Should I treat myself to prevent being infested?
No. Although anyone living with an infested person can get head lice, you don't need to be treated. Check household contacts for lice and nits every 2-3 days. Treat if lice and nits are found.
Should my pets be treated for head lice?
No. Head lice do not live on pets.
My child is under 2 years old and has been diagnosed with head lice. Can I treat with prescription or over-the-counter (OTC) drugs?
No. For children under 2 years old, remove nits, nymphs (immature adult lice), and adult lice by hand.
What OTC medications are available to treat head lice?
Many head lice medicines are available at your local drug store. Each OTC product usually contains one of the following active ingredients: - Pyrethrins: (often combined with Piperonyl butoxide, in Brand name products: A-200, Pronto, R&C, RID, Triple X) Pyrethrins are natural extracts from the chrysanthemum flower. Though safe and effective, pyrethrins only kill crawling lice, not unhatched nits. A second treatment is recommended in 7-10 days to kill any newly hatched lice. Treatment failures are common.
- Permethrins: (Brand name product, NIX) Permethrins are similar to natural pyrethrins. Permethrins are safe and effective and may continue to kill newly hatched eggs for several days after treatment. A second treatment may be needed in 7- 10 days to kill any newly hatched lice. Treatment failures are common.
What is the prescription drug used to treat head lice?
Lindane is the prescription drug and is one of the most common treatments for head lice. When used as directed, the drug is probably safe. Overuse, misuse, or accidentally swallowing Lindane can be toxic to the brain and nervous system.
Which head lice medicine is best for me?
If you are unsure, please consult with your pharmacist or health care provider.
What are the rules with head lice medicines?
When using head lice medicine, as with any medicine, always follow the instructions provided.
When treating head lice: - Do not use extra amounts of the lice medication.
- Do not treat the infested person more than 3 times with the same medication if it does not seem to work. See your health care provider.
- Do not mix head lice medications.
Should household sprays be used to kill adult lice?
No. Spraying the house is NOT recommended. Fumigants and room sprays can be toxic if inhaled.
Should I have a pest control company spray my house?
No. Vacuuming floors and furniture is sufficient to treat the house.
Based in part upon information from the Centers for Disease Control and Prevention (CDC). - Head lice are insect parasites that are found on human heads. Lice is plural for louse.
- Head lice are spread by personal contact or the sharing of combs, brushes, caps and other clothing.
- Head lice are a common problem with preschool and school children.
- Head lice cause a tickling feeling of something moving in the hair, itching, and sores on the head.
- The affected individual, family members also infected, and the home all should be treated.
- Remember: 1 head louse + 1 head louse = 2 head lice = the beginning of a head lice infection.
Last updated on 07/03/2008
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