Pediculosis capitis is another term for infestation with head lice (Pediculous humanus capitis).

The head louse is an obligate human parasite that lives exclusively on scalp hair. Transmission occurs mostly via direct head-to-head contact. The head louse can survive up to 4 days on fomites such as brushes, barrettes, and headgear; therefore, indirect transmission is possible. In one study, live lice were found on the pillowcases of 4% of infested study volunteers.

School-aged children, particularly girls, have the highest incidence, but head lice are present worldwide and affect all socioeconomic classes. All races and ethnicities are affected, with the exception of those with coarse, curly hair that lice are not able to properly attach to.

Outbreaks may occur in settings where there is close contact and/or frequent sharing of hair accessories, such as schools, day care centers, and nursing homes.

Worldwide incidence of pediculosis appears to be on the rise, most likely due to growing resistance to therapy.