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Pediculosis capitis is an infestation of adult lice or nits (eggs) in the hair on the head. The head louse lives close to the scalp and are most visible behind the ears or at the base of the neckline. Lice depend upon human blood to exist and can only survive up to two days away from the scalp. The main symptom of a head lice infestation is itching.
Optimally, eggs hatch in a week, and the resultant lice are capable of multiplying in 8-10 days. The typical adult louse lives 20-30 days and lays 4-5 eggs a day; however, the eggs will only hatch if they are less than 1 week old and are near the scalp.
Mode of Transmission
Transmission occurs by direct head to head contact with a person with a live infestation, or less frequently, direct contact with their personal belongings that are harboring lice, such as combs, hairbrushes or hats.
Period of Communicability
A person can spread lice as long as live lice remain on an infested person and/or eggs (nits) in hair are within a ¼" from the scalp. Head lice are most common among children attending child care or elementary school.
School nurses should work with their administration and LHDs to implement a policy regarding head lice and attendance. A lack of scientific evidence hinders the ISDH from endorsing any policy; however, it should be noted that most school systems no longer support a “no-nit” policy.
Indiana State Department of Health Quick Fact Link:
Centers for Disease Control and Prevention (CDC) Link:
Harvard School of Public Health Link: