The head louse, or Pediculus humanus capitis, is a parasitic insect that can be found on the head, eyebrows, and eyelashes of people. Head lice feed on human blood several time a day and live close to the human scalp. Head lice are not known to spread disease. An estimated 6 to 12 million infestations occur in the U.S. annually. It is particularly common among pre-school and elementary school children. Personal hygiene or cleanliness in the home or school has nothing to do with getting head lice.

Head lice move by crawling; they cannot hop or fly. Head lice are visible to the naked eye. The eggs look like yellow, tan or brown dots on a hair. Live lice can also be seen crawling on the scalp. When eggs hatch, they become nymphs (baby lice). Nymphs grow to adult lice within one or two weeks of hatching. An adult louse is about the size of a sesame seed. Lice feed on blood from the scalp several times a day. They can also survive up to two days off of the scalp.

Head lice are spread through head-to-head contact; by sharing clothing, linens, combs, brushes, hats and other personal products; or by lying on upholstered furniture or beds of an infested person. You may be able to determine if your child has head lice by parting the child's hair and looking for nits or lice, particularly around the ears and nape of the neck. If one member of your family is diagnosed with head lice, you'll need to check on every member of the same household.

Multiple treatment options exist that are over the counter. They include shampoos, cream rinses and lotions. The active ingredients include pyrethins, permethrin, malathion and benzyl alchohol. Prescription drugs are available for resistant cases. It is important to use these medications exactly as instructed and for the full course of treatment to eliminate the lice. Usually, 2 treatments separated by 7 to 10 days is necessary to kill any newly hatched lice.

Do not use a cream rinse, conditioner or combined shampoo and conditioner on your hair before a lice treatment.

You also should not shampoo for one or two days following the application of a treatment. After applying the medicated treatment, use a special comb or meticulous "picking" with your hands to remove nits on the hair. Repeat the entire treatment seven to ten days after the initial treatment to take care of any newly hatched lice. Please note that you should not treat a person more than three times with any individual lice medication.

In addition to treating the infested person, preventative measures include:

  • Wash all bed linens and clothing warm by the infested person in very hot water.
  • Dry clean clothing that is not machine washable.
  • Vacuum upholstery in your home and car.
  • Any items, such as stuffed toys, that can’t be machine-washed can be placed in an airtight bag and stored away for two weeks. Lice cannot survive this long without feeding.
  • Soak combs, brushes, headbands and other hair accessories in rubbing alcohol or medicated shampoo for at least one hour or throw them away.

If your child still has head lice after two weeks with over-the-counter medicated products, contact your dermatologist for other treatment options.

For more infomation about head lice, including treatment options visit the CDC website:

http://www.cdc.gov/parasites/lice/head/