Clinical Course
Onset of seabather’s eruption generally occurs within a few minutes to several hours after the swimmer leaves the water. A pruritic maculopapular rash, occasionally with urticaria, spreads across the skin of the chest, abdomen, neck, axillae, and the flexor surfaces of the arms and legs. The rash may be accompanied by systemic symptoms of malaise, headache, fever, chills, nausea, and vomiting. The dermatitis often lasts 3 to 7 days, but more severe reactions can last up to 6 weeks.3
Are immunological mechanisms responsible?
Tomchik et al4 observed several cases of secondary eruptions that occurred 5 to 10 days after initial exposure. They also reported cases in which urticarial lesions developed 3 weeks after onset of illness, following a disease-free interval during which there was no re-exposure to ocean water. The lesions were seen in the same areas as the initial eruption.
This suggests that immunological mechanisms are responsible for the various clinical courses observed, which would explain the lack of symptoms immediately after exposure, delayed onset of the dermatitis, urticaria among sensitized individuals, and the ability of steroids to suppress the reaction.
A prospective cohort study of cases in Palm Beach County, Florida, concluded that persons with a history of exposure to the condition, children, and surfers were at greatest risk for seabather’s eruption.5