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 …
The antibody response in seabather's eruption.
Thirty-six of 44 patients with seabather's eruption had specific IgG antibodies against Linuche unguilata (thimble jelly) medusae antigen. ELISA detected antibodies in serum stored for 10 years. The extent of the cutaneous eruption or sting severity was correlated with antibody titer. Antibodies were detected in patients acquiring the eruption in Florida, the Bahamas and Aruba, reflecting the habitat of these jellyfish. This serological assay can be useful to confirm the clinical diagnosis.
The effect of verapamil on the cardiotoxic activity of Portuguese man-o'war (Physalia physalis) and sea nettle (Chrysaora quinquecirrha) venoms.
Verapamil, a calcium antagonist, is effective in delaying death in mice after i.v. challenge with sea nettle (Chrysaora quinquecirrha) or Portuguese man-o'war (Physalia physalis) crude venom. Death caused by these venoms could also be delayed by prior medication of the animals. Continuous EKG monitoring of sea nettle venom-challenged rats demonstrated that a single rapid injection of verapamil might require 4 min to be effective and that up to four repeated injections may be necessary to counteract the venom-induced abnormalities. Verapamil reduced the sea nettle venom-induced positive inotropic effect on isolated guinea pig atrial strips. These data further indicate the effectiveness of verapamil as a therapeutic agent against jellyfish cardiotoxins.