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 …
Jellyfish envenomation syndromes.
Jellyfish venoms are complex mixtures of polypeptides and enzymes pathogenic to man by means of their toxic or antigenic properties. With newer technology, more therapeutic agents will become available to treat the various envenomation syndromes caused by these animals. It will therefore be necessary to make an accurate diagnosis of the type of reaction the patient experiences, as well as to identify the offending species. Fatal reactions can be caused by hypersensitivity or induced by various toxins on the heart, respiratory center, or kidney. Cutaneous eruptions may be local or generalized, have exaggerated local edema, become recurrent, be delayed and persistent, or occur at sites distant from the primary sting. Fat atrophy, pigmentary changes, and contractures with gangrene can also appear. Identification of the responsible coelenterate can be made directly by actual visualization or indirectly by the knowledge of location, time, and environmental circumstances of the stinging. First-aid measures designed to prevent additional nematocyst rupture appear to be species-specific. Anaphylaxis should be counteracted by the lifesaving measures required. Other syndromes, either caused by toxic effects of the venom or mediated by humoral or cellular immune mechanisms, should be treated by means designed to interfere with their pathogenesis.
First Aid for Jellyfish Envenomation
ABSTRACT: To determine a reliable first aid topical remedy for jellyfish stings, we investigated several commonly available preparations to determine their ability to prevent nematocyst rupture from sea nettle (Chrysaora quinquecirrha) and Portuguese man-of-war (Physalia physalis) tentacles. The application of a baking soda slurry was a good inhibitor of nematocyst discharge for the nettle and vinegar was a good inhibitor for the man-of-war.