Lesson of the Week: Seabather's eruption—a case of Caribbean itch
Seabather's eruption is an intensely pruritic dermatitis that occurs after exposure to seawater and affects the areas of the body covered by swimwear. It has probably existed for centuries, but formal reports of it are relatively recent.1 With the increasing popularity of foreign travel, seabather's eruption is likely to be seen more often in patients returning from tropical climes. Larvae of species belonging to the phylum Cnidaria—which comprises jellyfish, corals, sea anemones, and hydra—have been implicated as the cause of this condition.2 3 4 The members of this phylum share a similar stinging mechanism, which is mediated by subcellular organelles called nematocysts. We report two recent cases of seabather's eruption caused by the larvae of thimble jellyfish (Linuche unguiculata).

Seabather's eruption should be suspected if there is a history of exposure to seawater followed by the appearance of a papular, pruritic rash affecting the areas covered by the swimsuit

In May a 31 year old accountant and her husband travelled to Cancun, on the Caribbean coast of Mexico, for their honeymoon. On the last day of the trip they took a final swim in the ocean, and within minutes of entering the water they became aware of a …
Caribbean Itch: Eight Cases And One Who Didn’t (Exercise Blue Calypso Diamond)
Stinging plankton are a potential source of irritation and morbidity for those pursuing aquatic sports in areas where they are numerous. The problem is seasonal, and likely to be familiar to local people. We describe an incident in which a number of military personnel were affected by the stings of the thimble jelly fish (Linuche unguiculata), with a brief review of the biology of the problem and some recommendations for prevention.
Recurrent eruption following a solitary envenomation by the cnidarian Stomolophous meleagris.
The case history of a patient who developed a linear erythematous eruption on the ankle after envenomation by Stomolophous meleagris is described. This eruption subsided within 20 hr and recurred without subsequent envenomation 7 days later. The recurrent eruption was similar in morphology to the original lesion, but was accompanied by stiffness and edema. Examination of biopsied skin from the recurrent eruption showed a perivascular mononuclear cell dermal infiltrate. No abnormal deposits of immune globulins or complement were found in this specimen. The patient's serum contained antibodies to Stomolophous antigen and two other jellyfish. Two screening tests of lymphocyte function were negative upon exposure to Stomolophous antigen. This was the first reported case of recurrent local eruption to a single human envenomation by this coelenterate, which usually is regarded as relatively harmless to man.