School management and exclusion policy for head lice

What it is

Pediculosis capitis is a hair infestation caused by Pediculus humanus capitis, the head louse. It is a relatively common infestation in school-aged children and adolescents, but it is often unnecessarily feared and affected children are stigmatized.

How it spreads and who gets it

Head lice spread by close physical contact or by sharing fomites such as clothes. Children 3-11 years of age are commonly affected. The point that decides the school question is that transmission rates are relatively low in the classroom setting.

How it presents and how it is diagnosed

The infestation causes scalp pruritus, with or without lymphadenopathy.

Diagnosis rests on physical examination, by seeing lice and nits. Nits are louse eggs and do not necessarily represent an active, infectious case of head lice, so a clear diagnosis means live lice are seen.