• Knowledgebase: Information on Specific Illnesses

    Here you will find discussions of specific illnesses and their management.

    52. Head Lice - Top

    Tiny parasitic insects (Pediculus humanus capitis) that live on the scalp and can be spread by close contact with other people.

    Causes, Incidence and Risk Factors

    There are three common types of lice: head lice,body lice, and pubic lice. Head lice infect the scalp hair and are easiest to see at the nape of the neck and over the ears. Small eggs (nits) can be seen on the hair shafts. They appear much like flakes of dandruff, but are stuck firmly to the hair shaft instead of flaking off of the scalp. Head lice do not cause a serious medical problem and do not spread other diseases (as body lice do), but they are spread very easily. Risk factors include close, overcrowded living conditions, and poor hygiene. Lice spread readily among school children.


    Symptoms
    intense itching on the scalp
    lice on scalp and clothing (these may be difficult to see unless the infestation is heavy)
    eggs on hair shaft (these appear as tiny white specks firmly attached to the base of the hair shaft)
    Signs And Tests

    Examination is sufficient to determine the presence of lice. The infestation may be confined to the scalp or may include the surface of the body (body lice) including the groin area (pubic lice).


    Treatment

    Over-the-counter and prescription lotions and shampoos are available that are reasonably effective. Evidence of increasing resistance to these pediculocides is growing making it increasingly difficult to clear up infections. Bed clothing, combs, brushes, hats and other personal hygiene items must be disinfected (typically washed in hot soapy water) to prevent re-infestation. This should be done at the time the child is treated.
    Examples of medications used include:

    Kwell lotion (available by prescription only)
    Nix (available over-the-counter)
    Rid (available over-the-counter)
    It should be remembered that these medications are, in reality, insecticides and should be used exactly as directed and no more frequently than recommended in the package insert.New products are available that loosen the bond between the nit (egg sack) and the hair shaft so that the nits can be easily removed. Removal of all nits may prevent reinfection if the medication fails to kill all of the eggs.Some physicians have recommended smothering the lice as an adjunct to standard treatment since resistance to the pediculocides is increasing. They recommend copious amounts of olive oil rubbed into the hair, covered with a shower cap and left on overnight.

    Expectations (Prognosis)

    The lice are usually killed with treatment. Re-infestation is possible, and if the source of the infestation is not corrected (for example a classroom with many infected children) the re-infestation is probable.

    - Updated: March 5, 2001

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    • James L Horwitz, MD

    David C. Thomas, MD

    Barbara Lindberg, PNP