Head louse infestations: the "no nit" policy and its consequences.

Health authorities in the USA, Canada and Australia recommend a "no nit" policy, i.e. the immediate dismissal of all children who have head lice, eggs and/or nits on their hair from school, camp or child-care settings. These children would be readmitted to the institution only when all head lice, eggs and nits have been removed. The "no nit" policy assumes that all nits seen when examining the scalp are viable and therefore the infested individual should be treated for lice, and all nits must be removed from the scalp. However, it has been repeatedly shown that only a small number of children who have nits on their scalp are also infested with living lice. Accordingly, in the USA alone 4-8 million children are treated unnecessarily for head lice annually, which amounts to 64% of all lice treatments. In addition, 12-24 million school days are lost annually. The annual economic loss owing to missed workdays by parents who have to stay home with their children adds US$4-8 billion to the country's economy. The policy also results in serious psychological problems for children and their parents. Therefore, the "no nit" policy should be abandoned and alternative ways of examination and treatment for head lice should be found.