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Blood sucking insects which are obligate human parasites.
Three major types.: Pediculus humanus capitis (head louse) which live on the scalp, Pediculus humanus corporis (body louse) which lives in clothing, and Phthirus pubis (pubic louse) which lives mostly in pubic hair.
Head lice attaches its eggs or nits to the hair shaft and affects mainly children and others with long hair.
Head lice transmission occurs from human to human and from the sharing of combs and hair brushes.
Among homelessness the prevalence of body lice ranges from 5.4 to 35%.
Body lice infestation occurs in individuals who are unable to maintain personal hygiene: homelessness, displaced persons who do not have frequent access to washing facilities, and individuals with mental illness, cognitive impairment, or physical disability with unmet needs to support activities of daily living.
Body lice live on clothing.
Body lice are visible to the eye.
Body lice require five blood meals daily to survive and prefer clothing seams in close proximity to the skin.
Body lice are attached the skin when obtaining a blood, but do not borrow into the skin.
Cutaneous manifestations reflect hypersensitivity reactions to lice.
Skin findings are non-specific and most commonly include erythematous and often excoriated macules, papules or plaques, hyperpigmentation, and lichenification.
Bullae and urticaria may be seen.
Skin lesions are typically located in the lateral trunk waistline, medial and lateral legs and upper back/posterior shoulders with sparing of the central and mid back.
Clothing examination may demonstrate dozens to hundreds of lice where the skin may only have 10 or fewer lice.
Head lice associated with itching and dermatitis.
Head lice may be associated with secondary bacterial infections and lymph node enlargement.
Head lice diagnosis confirmed by the identification of lice and nits on hair.
Body lice may cause sytemic manifestations with anemia and secondary bacterial infections.
Treatment: the first line treatment and prevention of body lice is bathing, and laundering of clothing and bedding at least once a week in hot water and drying using a high heat cycle.
Treatment for pediculosis capitis is either malathion or permethrin.
Pyrethrins with piperidyl butoxide is an alternative treatment as is Ivermectin.
Combing the hair and removing hatching lice is helpful addition to insecticide treatment.
Bedding and clothing should be decontaminated.
Pyrethroid insecticide permethrin 1% associated with a 90% cure rate.
Malathion 0.5%, an effective alternative to permethrin.
Topical treatments should deliver high concentrations with a single application and the lotion should be applied to full coverage, a second application at day 7-11 will kill eggs that may have hatched after the first application (Chosidow O)..
Concomitant topical treatment for all infested family members is suggested (Chosidow O).