SEABATHERS ERUPTION

Background. Seabather's eruption is an annoying pruritic dermatitis th at appears on the areas covered by the bathing suit as an erythematous macular or papular dermatitis, with or without urticaria. It occurs s poradically in Florida, the Caribbean, and as far north as Bermuda. Th e cause is not known. Methods. We collected information in Nassau Coun ty, Long Island, New York, about cases of all types of water-related d ermatitis reported by beach personnel, health providers, and affected swimmers from 1970 through 1991. Concurrently, we surveyed all Nassau County swimming waters, especially during the summer season (June thro ugh September), for the presence of organisms capable of causing derma titis. In 1980 a sudden epidemic of a severe, unfamiliar dermatitis in ocean bathers prompted increased surveillance of cases and waters. Pl anula larvae of the phylum Cnidaria were collected from the ocean and beaches and inside bathing suits. They were examined, photographed, te sted on healthy subjects, and observed in the laboratory for metamorph osis. Results. Three outbreaks of seabather's eruption have occurred o n Long Island since 1975. The first, in August 1975, affected a small number of swimmers on the eastern end of Long Island. In 1980 there we re thousands of cases along the entire south shore of the island, and in 1990 there were hundreds in the same area. In nonepidemic years, fi ve or fewer cases have been reported yearly. Surveillance for larvae r evealed them to be present during the swimming season in epidemic year s, but in nonepidemic years they did not appear until autumn, after th e swimming season. Applying larvae to the skin of healthy subjects pro duced a dermatitis indistinguishable from seabather's eruption. All la rvae metamorphosed in the laboratory to the adult sea anemone Edwardsi ella lineata. Conclusions. Seabather's eruption, previously reported o nly as sporadic cases in southern climates, has occurred sporadically and in outbreaks 1000 miles north of most previously described cases. These Long Island episodes were probably caused by the planula larvae of E. lineata.