Cnidarian larvae dermatitis T63.6

Cnidarian larvae dermatitis (not to be confused with the so-called (freshwater) bathing dermatitis = swimmer`s itch), which occurs after swimming in the sea on the coasts of Florida, the Bahamas, the Philippines, Thailand and Brazil. The disease, which is endemic and seasonal, was first described in the USA on Long Iland in 1975.

Triggers are the 0.2-0.3cm large larvae of the cnidarians Edwardsiella lineata (sea anemone) and the jellyfish Linuche unguiculata (jellyfish).

Lesions occur almost exclusively on the hairy and clothed areas of the bathers. The larvae adhere between clothing and skin, dry out there and empty their nematode cysts.

Strongly itchy o,1-1,0cm big red papules and wheals. Some of the affected persons experience systemic symptoms with headaches, nausea and vomiting.

Remove swimwear; shower with sea water. Otherwise purely symptomatic therapy (systemic antihistamine, glucocorticoid ointments locally).

The changes heal spontaneously after 3-7 days.

1. Freudenthal AR et al (1993) Seabather's eruption. N Engl J Med 329:542-544.
2. Prohaska J et al (2019) Seabather's eruption. StatPearls Publishing; PubMed PMID: 29493932.
3. Reitzel AM et al (2009) Comparative anatomy and histology of developmental and parasitic stages in the life cycle of the lined sea anemone Edwardsiella lineata. J Parasitol 95:100-112.