Please Read: This site contains information about using pesticides. Pesticides can be dangerous if used improperly or carelessly. Always follow label instructions. The pesticide product label is the final word on the safe and legal use of pesticides. Questions about pesticide toxicity can be explored at the National Pesticide Information Center (NPIC). Control suggestions are intended for users in the state of Oregon, USA. Others should consult with local experts before relying solely on this information.

The head louse is commonly found in the hair above ears and on the back of the scalp. It measures about 1/8 inch long. Anyone can get head lice but young children are more susceptible than adults, girls are slightly more susceptible than boys. The chance of a head lice infestation goes up in schools where lockers and coat hooks are shared, not assigned. Head lice are spread by person to person contact and sharing of personal items like combs, hairbrushes, and head ware. The most important sign of a lice infestation is the presence of "nits", or lice eggs (see below) attached to head hairs.

Unlike the head louse, body lice spend much of their time on clothing, usually in areas where the cloth is in contact with the body. Eggs are laid on clothing as well. They generally occur in crowded, unsanitary conditions. Body lice are slightly smaller than head lice (about 1/7 inch long) but otherwise almost identical in appearance. Body lice are uncommon in most of the U.S. population.

As the name suggests crab lice look superficially like tiny crabs with their enlarged second and third pairs of legs. Its other common name, the pubic louse, also is suggestive of where it lives - in the pubic area - but it can spread to the chest, armpits, and even eyebrows. As with other lice, person to person contact is the most common means of transmission. There is no evidence that lice are involved in the transmission of venereal diseases, including AIDS.

Lice cannot survive off their human host for long. Therefore there is little benefit from treating the whole house with insecticide. Rather, you must concentrate your efforts on where lice live. Control requires medicated shampoos or lotions available now over-the-counter (OTC). Lindane was once the insecticide of choice and was only available by prescription. Today, Lindane has been replaced by safer and more effective products that can be purchased without prescription. Be sure to follow instructions completely. Nit removal (nit-picking) is extremely important. Use a good metal (not plastic) nit comb and carefully and gently comb through the hair starting at the scalp, working out. Bedding and clothing from infested individuals should be machine washed, separately, in hot water and dried under high dryer heat. It is common for family members of infested school children to become infested as well so all family members may be treated.

Detection of head lice often causes a near panic among grade school teachers, school nurses and parents. The panic may lead to extraordinary measures. Sometimes the infestation is real but sometimes it is not. In either case simple, prudent measures will alleviate the problem without resorting to extremes. There is no need to screen students before they are allowed to enter the school building. If a child is found to have head lice they should be treated at home with one of the lice shampoos and nit removal. Suspected cases of infestation can be confirmed by a dermatologist or medical entomologist.

National Pesticide Information Center

Iowa State University Entomology Internet Resources

OSU Extension Service

OSU Extension & Experiment Station Communications (Publications)