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FREQUENTLY-ASKED QUESTIONS ABOUT HEAD LICE

By: Michael Waldvogel and Charles Apperson, Extension Entomology
Insect Note - ENT/rsc-8


  1. WHAT ARE LICE?louse
    Lice are small, wingless, grayish-white insects with flattened, elongate bodies and somewhat oval heads. They are about 1/16 to 1/8 inch long.

  2. ARE THERE DIFFERENT KINDS OF HUMAN LICE?
    There are several species or kinds of lice that feed on people. One species feeds specifically on the head and is called the head louse.

  3. CAN HEAD LICE SURVIVE ON PETS?
    No, head lice are obligate parasites of humans, i.e., they must feed on humans in order to survive.

  4. HOW LONG DO HEAD LICE LIVE?
    Lice may live for several weeks on a person, but they rarely live more than 48 hours when removed from a person's body.

  5. CAN HEAD LICE HOP OR JUMP?
    No, head lice cannot hop, jump or fly. Their legs are adapted for grasping a person's hair.

  6. DO HEAD LICE SPREAD DISEASES?
    No, head lice are not known to transmit any disease agents. However, secondary infections may result if the skin is broken by repeated scratching.

  7. WHAT ARE "NITS"?
    Nits are louse eggs. They are small (about 1/32 inch), white to cream color, and oval in shape with a distinct cap. Nits are often the first sign of a head lice infestation.

  8. WHERE ARE NITS FOUND?
    Head lice glue their eggs to the base of the hair shaft, frequently behind the ears or on the nape of the neck.

  9. HOW MANY EGGS DOES A FEMALE HEAD LOUSE LAY?
    A female head louse produces about four eggs per day and a total of about 88 eggs during her lifetime.

  10. HOW DOES SOMEONE GET HEAD LICE?
    Lice are transmitted by close personal contact with an infested person or by sharing their articles of clothing and personal items such as hats, headbands, scarfs or caps, combs and brushes.

  11. HOW MANY HEAD LICE ARE USUALLY FOUND ON AN INFESTED PERSON?
    Typically, 10-15 head lice are found. The number of lice often depends on personal hygiene, for example, how often the person bathes, shampoos or changes and washes his/her clothing.

  12. WHO IS MOST LIKELY TO GET HEAD LICE?
    Head lice have been found on people of all socio-economic levels. Children, particularly those of elementary school age, are most likely to get head lice because of their close contact and social interactions with each other (e.g., sharing hats, combs and brushes).

  13. IS IT TRUE THAT AFRICAN-AMERICANS DO NOT GET HEAD LICE?
    No. Although factors such as hair texture may make African-Americans less likely than Caucasians to get head lice, they are not immune to becoming infested.

  14. HOW CAN YOU TELL IF SOMEONE HAS HEAD LICE?
    Lice cause intense itching of the scalp. Parents and teachers should watch for children who scratch their heads constantly or excessively. In such cases, check the scalp for nits or lice. If you're not sure what to look for, ask for help from someone who can positively identify the eggs or the insects.

  15. HOW CAN I CHECK MYSELF OR MY CHILD FOR HEAD LICE?
    One simple way to check for lice is to have the person hold their head over a light-colored towel. Then, brush the hair and scalp vigorously towards the towel. Dislodged lice will be found on the towel. Because infested people usually have few lice, you can easily miss finding them. It is important that you carefully and thoroughly inspect the person's head, particularly the back of their neck and around their ears. Remember: dandruff, oil droplets in the hair and even flakes of hair spray can be confused with nits. Use a magnifying glass to help check for nits. When in doubt, consult a physician or your local health office for assistance.

  16. WHAT SHOULD BE DONE IF YOU SUSPECT SOMEONE IS INFESTED?
    They should seek help from their physician, county health department or school nurse. The entire family needs to be examined and treated, if necessary. In the case of school-age children, notify the principal immediately. Other children in the class must be checked by a doctor, school nurse or other health official. Letters can be sent home to notify each family of the problem and the possible need for them to take measures to prevent further spread of lice to other family members. The letters should help solve the problem and should not be used to single out any child as the cause of the problem.

  17. WILL SOAP AND WATER KILL LICE?
    Shampooing with regular non-medicated shampoos can help prevent an infestation, but it will not eliminate an active one. Washable clothing, hats, head bands, bed linen, towels and other personal items (such as brushes and combs) should be washed in hot (120oF or higher) soapy water, then dried in a clothes drier for at least 20-30 minutes. Woolen or other non-washable clothing can be dry-cleaned, but this additional expense can be avoided by simply isolating the articles for 1-2 days. Items such as stuffed toys do not need special treatment; however, if it make you feel more at ease, you can put them in the clothes dryer for 45-60 minutes

  18. WHAT MEDICATIONS ARE EFFECTIVE AGAINST LICE?
    Several "over-the-counter" products (pediculicides) are available to you at most drugstores. These include RID®, A200® and R&C Shampoo®, and Nix®. Ovide®, a shampoo that contains the insecticide "malathion" is available by prescription.

  19. DO THESE MEDICATIONS KILL THE EGGS?
    Over-the-counter products work well against the nymphs and adults, but most will not kill the eggs. Read the product labels carefully. Consult your family doctor about what is best for you to use.

  20. HOW IMPORTANT IS IT TO KILL THE EGGS?
    Mechanical removal of louse eggs helps reduce the number of lice that might hatch on the scalp. Even if you use Nix, the egg "shells" may remain attached to the hairs, giving the impression of an active infestation. Since children who are declared "nit-free" can return to class sooner, removing nits has a positive impact on their morale and lessens disruption to their school activities. Special combs are provided with the pediculicides and should be used according to the product instructions. Nits are more easily removed after shampooing the hair, when it is still damp.

  21. DO VINEGAR RINSES HELP REMOVE LICE EGGS?
    No, vinegar will not dissolve the cement-like substance that the female louse uses to attach her eggs to the hair shaft. A nit comb is the only real reliable method for removing the eggs. Although trimming the hair is not necessary, it does makes it easier to remove all of the nits..

  22. DO I NEED TO SPRAY MY HOME WITH AN INSECTICIDE IF SOMEONE IN MY FAMILY HAS HEAD LICE?
    No, lice cannot survive for more than about 24-36 hours when removed from a person and they do not live in cracks or crevices like cockroaches or other household pests. Spraying furniture, carpets and bedding with an insecticide serves no real purpose other than providing some margin of psychological comfort. Although such sprays kill an occasional stray louse, family members who are already being treated with insecticidal shampoos would be exposed unnecessarily to additional pesticides. If anything, vacuuming carpets and furniture will remove stray lice.

  23. WHAT ELSE SHOULD BE DONE IN THE CLASSROOM TO GET RID OF LICE?
    The need for delousing measures in a school depend largely on the age of the students and the layout of the classroom. As in the home, vacuuming carpeting and/or sleeping mats can help. Mats with vinyl or other non-fabric coverings can be cleaned with hot, soapy water. Clothing or personal items (such as those described in question 17) that students have left in a closet, storage area or desk should be removed and deloused. Application of insecticides in the classroom is not necessary and is strongly discouraged.


For information on the various lice that infest humans, see Insect Note ent/RSC-7, Biology and Control of Human Lice


Image of louse: Department of Entomology, University of Nebraska


Pest information and control recommendations presented here were developed for North Carolina and may not be appropriate for other states or regions. Any recommendations for the use of chemicals are included solely as a convenience to the reader and do not imply that insecticides are necessarily the sole or most appropriate method of control. Any mention of brand names or listing of commercial products or services in the publication does not imply endorsements by North Carolina Cooperative Extension nor discrimination against similar products or services. All recommendations for pesticide use were legal at the time of publication, but the status of pesticide registrations and use patterns are subject to change by actions of state and federal regulatory agencies. Individuals who use chemicals are responsible for using these products according to the regulations in their state and to the guidelines on the product label. Before applying any chemical, always obtain current information about its use and read the product label carefully. For assistance, contact the Cooperative Extension Center in your county.

Distributed in furtherance of the acts of Congress of May 8 and June 30, 1914. North Carolina State University and North Carolina A&T State University commit themselves to positive action to secure equal opportunity regardless of race, color, creed, national origin, religion, sex, age, or disability. In addition, the two Universities welcome all persons without regard to sexual orientation. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.



Last updated - 6/13/98

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