Lice are parasites, or insects, found on people's heads and bodies, including the pubic area. Human lice survive by feeding on human blood. Infestation or infested person means that a person has lice. You get lice (head, body, and pubic) from close person-to-person contact with someone who has a lice infestation. Dogs, cats, and other pets do not carry or spread human lice. Lice move by crawling; they cannot hop or fly. You can treat lice infestations with both over-the-counter and prescription medications.
People with head lice may not have symptoms, particularly with a first infestation or when an infestation is light. Itching (pruritus) is the most common symptom of head lice infestation. It is caused by an allergic reaction to louse bites. It may take four to six weeks for itching to appear the first time a person has head lice.
Other symptoms may include the following:
- A tickling feeling or a sensation of something moving in the hair
- Irritability and sleeplessness
- Sores on the head caused by scratching, which can sometimes become infected with bacteria normally found on your skin
Head lice do not transmit any disease and therefore are not considered a health hazard.
CDC's guidance has not changed—you do not need to send students with head lice infestation home early from school. They can go home at the end of the day, be treated, and return to class after beginning appropriate treatment. Nits may stay in hair after treatment, but successful treatment will kill crawling lice.