In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan.


Pediculosis (louse infestation) affects hundreds of millions of people worldwide each year and has been reported in all countries and within all socioeconomic classes. Lice are obligate, parasitic insects that have no free-living stage in their life cycle. They are transmitted by direct skin-to-skin or fomite-to-skin contact, and symptoms do not typically present for 3 to 4 weeks. The three varieties that are parasitic to humans are Pediculus humanus capitis (head louse), Pthirus pubis (pubic or crab louse), and Pediculus humanus (body louse). Head lice are the most common lice which cross all socioeconomic barriers, whereas body lice more commonly affect homeless and displaced populations and should be suspected in these groups when there are signs of scratching, poor hygiene, and in the colder months of the year.

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