Head Lice Fact Sheet

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What are head lice?

The head louse is an insect that can infest people. These tiny insects (about 1/8” long) make their home in human hair and feed on blood. Head lice multiply rapidly, laying small greyish-colored, oval-shaped eggs (called nits) which they glue to the base of the hair, close to the scalp. Head lice are not known to spread disease.

Who can get head lice?

Anyone can get head lice. They are not a sign of being dirty. Most people don’t know they are infested until they see the nits or lice. They are found throughout the world, most commonly on children.

How does a head lice infestation occur?

Head lice have no wings and do not fly or jump, but they can crawl or run through hair quickly. Most commonly, head lice are spread by direct head-to-head contact with an infested person. They may also be spread by sharing personal items such as combs, brushes, other hair-care items, towels, pillows, hats, and other head coverings. Dogs, cats, and other pets do not spread head lice.

What are the signs of a head lice infestation?

Look closely for nits along the hairline at the back of the head and neck and behind the ears. Nits should not be confused with an accumulation of hair spray, hair gels, or dandruff, which can be easily flicked off the hair; nits cannot because they are firmly attached to individual hairs.

One telltale sign of head lice is a persistent itching of the scalp, which is sometimes accompanied by infected scratch marks or what appears to be a rash.

If you have questions about the diagnosis of head lice, call your doctor.

How do you treat head lice?

The recommended treatment includes using either an over-the-counter (OTC) or prescription medicated (lice-killing) product. Effective head lice treatments include products such as:

• “Nix,” a cream rinse product available OTC which contains permethrin, a synthetic insecticide
• Many brands of pyrethrin-based shampoo products (“Rid,” “R&C,” “Triple-X,” etc.) which are also available OTC
• “Ovide,” a prescription drug containing malathion.

With all of these products, the lice are often killed with one treatment; however, a second treatment seven to 10 days later is often necessary to ensure all of the nits are killed. Because of increasing numbers of reports of treatment failure with the OTC products, make sure to carefully follow all the instructions on the product label and talk to your health care provider if lice persist. Additional prescription alternatives are available.

What are some examples of alternative treatments?

Many alternatives to OTC or prescription head lice control products have been suggested. Although there is little scientific information to support these methods, successful treatment has been reported using several alternative treatments when conventional treatments haven’t worked, or when there is a concern about the toxicity of using head lice control products repeatedly. The Minnesota Department of Health cannot recommend these treatments without further evidence of their effectiveness. However, we feel it is important to mention some of the more commonly used methods.

The alternative treatments listed below are referred to as suffocants. When applied, the treatment may suffocate and/or create a habitat unfavorable to the head lice.

• Petroleum jelly (Vaseline®)
• Mayonnaise
• Oil (e.g. vegetable, olive, or mineral)

Manual removal of lice and nits by parents or professional services may be an effective supplement or alternative to OTC and prescription treatments.

How should you clean up the environment?

Head lice cannot survive off the human body for more than two days. They do not reproduce off the body. They do not live on pets. Any nits that fall off the head will not hatch or reattach. While most head lice control should focus on treating infested people, some simple things can be done in the environment:

• Wash bedding in hot water (above 130° F) and dry in a hot dryer. Wash and dry recently worn clothing (including coats, caps, and scarves) in hot temperatures.
• Clean combs, brushes and similar items by heating in water of at least 130° F for 10 minutes.
• Clean floors, carpeting, and furniture by thorough vacuuming only. The use of insecticide sprays is not recommended.

Cleaning efforts should happen on the day of the first lice treatment and whenever live lice are found on the patient’s head. Focus on cleaning areas and items the infested person had contact with 48 hours before treatment.

How do you prevent a head lice infestation?

Parents are encouraged to check their children’s heads for lice on a regular basis throughout the year. Families should not depend on someone else to check a child’s head – this may delay treatment. Remember, if one person in a family, camp, or school has head lice, there’s a chance others will too. Check everyone, and use the same treatment if necessary. Treating people without lice or nits is not recommended.

How should schools control head lice?

Schools should encourage parents to check their children regularly for lice at home. Wide-spread head lice screening efforts by schools have not been shown to be effective.

When a case of head lice is suspected, parents should be advised at the end of the day to check their children for lice and treat them if an infestation is found. Children with head lice infestations can go to school.