By Gary M. White, MD

Swimmer's itch Multiple very itchy papules one day after water sports in a Michigan lake. "Lake itch".

Swimmer's itch, aka, Cercarial dermatitis is caused by the penetration of human skin by cercariae of schistosome parasites that develop in and are released from snail hosts. Cercarial dermatitis is usually acquired in freshwater habitats, and less commonly in marine or estuarine waters.


Small, inflammatory papules develop in the the skin not covered by the bathing suit, in contrast to sea bather's eruption, in which the lesions occur in skin covered by the bathing suit.

Additional Pictures

Swimmer's itch Swimmer's itch Swimmer's itch


J Travel Med. 2006; 13(3): 166–171.


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