Pediculosis (Lice)

Pediculosis capitis– Infestation by lice of the head, body, or pubic areas.

Causes and Incidence

Two species of lice cause pediculosis. Pediculus humanus affects the head and body, andPhthirius pubis infects the pubic area as well as eyebrows, eyelashes, and axillae. In pediculosis capitis (head lice), the lice on the scalp are transmitted by personal contact and through objects such as combs and brushes. In pediculosis corporis (body lice), the lice live in unclean underclothing and periodically feed on the skin. In pediculosis pubis (pubic lice), the lice live at the base of curly hairs, chiefly in the genital region, and are transmitted primarily by sexual contact or very close personal contact. Infestation is widespread in areas with crowded, unsanitary living conditions. Head liceare common in day care centers, schools, and other places with large numbers of children who share personal items.

Disease Process

The lice bite the skin and inject saliva during feeding, causing severe pruritus. Scratching causes excoriation and secondary infection. Each day, female lice lay eggs (nits), which cement themselves to the base of the hair shaft in the head and pubic forms. These eggs hatch in 8 days.


Itching, excoriation, and secondary infection of bite lesions are common signs. Grayish white nits may also be observed at the base of hair shafts, as can the lice themselves.

Potential Complications

Furunculosis is an occasional complication. The lice also serve as vectors for organisms that cause typhus, trench fever, and relapsing fever.

Diagnostic Tests

A physical examination revealing nits or lice. The examination may be enhanced using fluorescent light and microscopic examination of hair shafts.



Antiinfective shampoos, creams, lotions, and ophthalmic solutions to kill lice and nits– must be used again about 8 to 10 days after initial treatment to kill remaining hatching nits.

Nit combs to comb out nits; elimination of body lice from clothing and bedding by washing, boiling, and steaming; elimination of lice from combs and brushes by boiling; vacuuming of carpets and upholstered furniture; cutting fingernails short and using gloves to prevent damage by scratching; prevention by instituting sanitary conditions, encouraging children not to share combs, brushes, caps, scarves, and other articles of clothing; school and community prevention and early detection programs.