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About Head Lice

The tiny parasitic insects known as head lice can infest the head and neck area and attach their eggs to the base of the hair shaft. Head lice do not cause disease, but they can itch and irritate the scalp, leading to scratching and potential bacterial infection.

Head Lice Transmission

Head lice can be passed from person to person. Usually this occurs during direct head-to-head contact, such as children playing or reading together, sharing a bed during slumber parties, or playing sports that involve direct contact.

Less often, head lice can be spread by sharing bedding, combs and brushes, hats, or clothing.

Head lice do not fly or jump; they cannot be transmitted without direct contact or sharing items.

Inspecting for Head Lice

Head lice often cause itching and scratching of the scalp, but some people who have head lice may not notice any itching. If a child has head lice, all family members and close friends should be checked for lice.

If you believe your child has head lice, you will need to check their scalp. Use a bright light, such as a flashlight or direct sunlight so you can see clearly. You may need a magnifying glass or reading glasses to see the tiny lice or nits (eggs). 

Adult lice are about the size of a sesame seed, but young lice may be smaller. They range in color from almost clear to black. They may be crawling quickly.

Even if you don’t see live lice, you may find nits (eggs). Debris and dandruff can be easily removed, nits cannot. Nits look like white or clear ovals glued tightly to the hair shaft. They will be located within 1/2 inch of the scalp; nits further than 1/2 inch from the scalp have already hatched.

Treating Head Lice Infestations

Even the best personal hygiene cannot prevent head lice infestation. You cannot shampoo away head lice or their eggs (nits).

Lice shampoo can be purchased over the counter from most drugstores, or may be obtained by prescription from your doctor. These products must ALWAYS be used exactly as directed by the label or a medical professional.

NEVER use other insecticides, household products or products meant for animals in place of registered head lice shampoos. These products have not been tested for safety when used in this way, and may be harmful to the person being treated.

Lice shampoo is intended to kill adult lice; it cannot kill the lice nits (eggs). After shampooing, you MUST comb the hair thoroughly using a special lice comb. Before the hair dries, comb and part it into sections. Use the lice comb to examine small sections of hair for nits or remaining adult lice, and remove them with your fingernails, the comb, or by cutting the strand of hair with scissors. Use soapy water to drown any live lice or nits you find. This process may take a while, but is very important to prevent re-infestation.

Treating the Household

You should treat all affected family members at the same time. Treat only the family members who actually have lice.

After treatment, launder all bedding where affected family members sleep. Items that cannot be laundered, like stuffed animals, can be sealed in a plastic bag for two weeks to allow lice to die. Vacuum floors and upholstered furniture.

You do not need to use household insecticides to treat head lice infestations. Head lice cannot survive more than a few days if they are not on a person’s head, and nits will not hatch. You only need to treat items that have been in close contact with an infested person in the days prior to treatment.

Combs, hairbrushes, and hair ornaments used by a person with head lice should be disinfected to remove any lice or nits.

More Resources

US EPA’s Head Lice Control page

CDC’s Head Lice Treatment FAQ

Head lice information from California Department of Public Health (English, Spanish)

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