About: 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 times a day and live close to the human scalp. Head lice are not known to spread disease. An adult head louse is about the size of a sesame seed, has six legs, and is usually tan or grayish-white in color. A mature female louse can lay up to 10 eggs per day. These tiny eggs (nits) are attached firmly to the base of the hair shaft within about 4 mm of the scalp. The eggs typically hatch within 7-12 days.
Head lice do not jump or fly, but rather move through the hair by crawling. Movement of the lice through the hair causes the itching associated with an infestation. In almost all cases, infestation occurs through direct contact. Indirect infestation is much less likely, but children should be taught not to share personal items such as brushes, combs, and hats, Lice do not carry disease and are not a sign of poor hygiene.
Treatment: The best way to avoid a chronic problem is to perform regular checks of all family members. Infestations should be treated promptly and completely. The American Academy of Pediatrics and the California Department of Public Health recommend treatment with over-the-counter products containing permethrin or pyrethrins, such as Nix or Rid medicated shampoos. After using the product according to package directions, follow-up with nit removal and wet combing. Re-check and remove nits frequently until hair is clear.Eggs will not hatch once off the head, and an adult louse can only survive for about 24 hours away from the scalp. For these reasons, excessive housecleaning following an infestation is not necessary. Clothing and bedding recently used should be washed and dried. Thoroughly vacuum carpets. Stuffed animals and pillows can be put in the clothes dryer on high. Home "lice sprays" have not been proven effective.
Lice & Attendance: If a student is found with active, adult head lice, they shall be allowed to stay in school until the end of the school day. The parent/guardian of any such student shall be given information about the treatment of head lice and encouraged to begin treatment of the student immediately and to check all members of the family. The parent/guardian also shall be informed that the student shall be checked upon return to school the next day and allowed to remain in school if no active head lice are detected.
Sources: American Academy of Pediatrics Clinical Report on Head Lice (May 2015) and Mill Valley School Board Policy 5141.33