These brothers, age 6 and 8 years old, developed an intensely itchy rash immediately after swimming at a beach near Boston. Itching occurred within minutes of leaving the water, blanching papules with central pustules developed several hours later, and small blisters appeared on day 3. Complete resolution occurred in about a week. They were treated with an oral antihistamine and a topical corticosteroid. Cercarial dermatitis of swimmer's itch is caused by cercariae of Schistosoma species that do not infest humans as part of their natural life cycle. On initial exposure there is only minimal response. However, once sensitized the reaction is usually brisk with the development of papules, pustules and vesicles on exposed areas of skin. On the contrary, seabather's eruption, which has been attributed to jelly fish species, usually involves clothing covered sites where the organisms are trapped under tight fitting garments.
symmetric, widespread, edematous red plaques with central vesicles and pustules