The patient was given a diagnosis of seabather’s eruption (SBE), also called seabather’s dermatitis or sea lice. SBE is an intensely itchy papular-erythematous dermatitis that can develop after an individual has been swimming in the ocean.
Planula larvae of the scyphomadusae Linuche unguiculata—commonly known as the thimble jellyfish—are to blame for this form of dermatitis. L unguiculata are most frequently found in the waters of the Caribbean, Gulf of Mexico, southern United States, and South America. Cases of SBE are most common in the spring and summer months, peaking in May. Those at highest risk include children, people with a history of SBE, and water sports enthusiasts (eg, surfers).
SBE usually resolves spontaneously within a week or 2. If treatment is necessary, start with topical corticosteroids and oral antihistamines. If this proves insufficient, move on to oral corticosteroids. To minimize risk, swimmers should remove their bathing suits and shower as soon as possible after leaving the water.
In this case, the physician advised the patient to take diphenhydramine (Benadryl) and the itching went away.
Adapted from: Monckton R, Fagan B, Frayne DJ, et al. Photo Rounds: Pruritic erythematous maculopapular rash. J Fam Pract. 2011;60:613-615.
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