Infestation with the head louse, Pediculus humanus capitis, is common. It is highly contagious and spread by direct head-to-head contact. Scalp itch leads to scratching, secondary infection and cervical lymphadenopathy. The diagnosis is confirmed by identifying the living louse or nymph on the scalp or on a black sheet of paper after careful fine-toothed combing of wet hair following conditioner application. The empty egg cases (‘nits’) are easily seen on the hair shaft and are hard to dislodge.
Treatment is recommended for the affected individual and many infected household school contacts.Eradication in school population is difficult because of poor compliance and treatment resistance.Malathion, premethrin or carbaryl, in lotion or aqueous formulations, should be applied twice at an interval of 7-10 days. Rotation treatments within a community may avoid resistance. Regular ‘wet-combing’ (physical removal of live lice by regular combing of conditioned wet hair) may be less effective than pharmacological treatments. Vaseline should be applied to eyelashes brows twice daily for at least a fortnight.
These are similar to head lice but live on clothing, particularly in seams, and feed on the skin. Poor hygiene and overcrowded conditions predispose. Itch,excoriation and secondary infection occur. Dry cleaning and high temperature washing or insecticide treatment of clothes are required.
Pubic (crab) lice
Usually, these are sexually acquired and very itchy. Malathion or carbaryl in an aqueous base easy treatment of choice, applied on two occasions to the whole body, as body hair can also be infested. Contacts should also be treated.