Head lice epidemiology and demographics

Template:Head lice Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

In the United States, infestation with head lice (Pediculus humanus capitis) is most common among preschool- and elementary school-age children and their household members and caretakers. Head lice are not known to transmit disease; however, secondary bacterial infection of the skin resulting from scratching can occur with any lice infestation.

Epidemiology and Demographics

Having head lice is very common. However, there are no reliable data on how many people get head lice in the United States each year.

Occasionally, head lice may be acquired from contact with clothing (such as hats, scarves, coats) or other personal items (such as brushes or towels) that belong to an infested person.

Age

Preschool and elementary-age children, 3-11, and their families are infested most often.

Sex

Girls get head lice more often than boys, women more than men.

Developed Countries

In the United States, African-Americans rarely get head lice.

Reliable data on how many people get head lice each year in the United States are not available; however, an estimated 6 million to 12 million infestations occur each year in the United States among children 3 to 11 years of age. Some studies suggest that girls get head lice more often than boys, probably due to more frequent head-to-head contact.

In the United States, infestation with head lice is much less common among African-Americans than among persons of other races. The head louse found most frequently in the United States may have claws that are better adapted for grasping the shape and width of some types of hair but not others.