The 2-3 mm long human head lice, Pediculus capitis, are insects that live on human hairs and survive by sucking blood from the skin. They are very common and spread from one person to another very quickly by close contact, by sharing a brush or comb, or by wearing another person’s hat.
The female louse lays eggs and glues them to the hairs (nits). They hatch after six days, grow into adults capable of further reproduction in about ten days and live for four to six weeks. The nits that can be seen firmly attached to hairs are the egg cases.
Often there are no symptoms, but in severe cases there may be a mild itching on the scalp. The most common areas for them to congregate are the forehead and behind the ears.
It is advisable to treat all the members of a family with lotions or shampoos that contain malathion or gamma benzene hexa chloride. Treatment should be repeated weekly for two or three weeks to kill insects as they hatch. The hair does not need to be cut short unless there are repeated infestations. Eggs that remain after treatment may be removed with a fine comb.
Another very effective method of treatment is to wash the hair, then apply conditioner, but do not rinse out the conditioner, and the lice will be unable to grasp the hair and can be combed out.
Lice cannot survive for long away from humans, so clothing and pillows need only normal washing and no special treatment. If there is any doubt about the diagnosis or the problem becomes recurrent, medical advice should be sought.
Exclusion of children with head lice from school is only necessary until proper treatment has been given. A cure is possible with correct treatment.