Dermatitis Caused by Coelenterates

Abstract

The phylum of Coelenterata (Cnidaria), animals that have a worldwide distribution, includes four toxic classes: Anthozoa (sea anemones, true hard and soft corals and sea pens), Scyphozoa (true jellyfish), Hydrozoa (physalia and fire corals: not true corals), and Cubozoa (box jellyfish). Highly specialized cells (nematocytes) are present on the surface of Coelenterata, and associated with the venom discharged during stings. An organ synthesized by the nematocytes, the nematocyst, is expelled in a harpoon-like fashion during a nanosecond process, and injects different active toxic substances into the prey. Injuries caused by cnidarians are of two pathogenic orders, toxic (the most common mechanism) and allergic (of immediate or delayed type). Different clinical pictures can arise after Cnidarians envenomations, featuring skin and systemic reactions that can even be fatal. True jellyfish induce a great number of accidents in the world, although they are generally less severe than those caused by box jellyfish and physaliae. Box jellyfish are among the most significant toxic marine animals, and their envenomation usually presents as a medical emergency. Sea anemones can cause cutaneous and systemic manifestations, including seabather’s eruption, characterized by pruriginous papulous lesions that persist for 1–4 weeks. True corals provoke skin lesions through toxic and traumatic mechanisms. Physaliae stings are usually painful and severe, and go together with systemic manifestations that can involve various organs. Reactions to fire corals are also very severe. A correct diagnosis and appropriate treatment are essential in cases of cnidarian envenomations, particularly because specific antivenoms are lacking.