The population growth along coastal areas has made exposure to hazardous marine fauna increasingly common. The popularity of home aquariums generates additional exposures inland. Marine fauna can inflict injury through direct traumatic bite or envenomation, usually via a stinging apparatus.
Major marine trauma includes bites from sharks, great barracudas, moray eels, seals, crocodiles, needlefish, wahoos, piranhas, and triggerfish. Shark bites may also cause substantial tissue loss, particularly the legs, with hemorrhagic shock. Minor trauma is usually due to cuts and scrapes from coral which can cause local stinging pain, erythema, urticaria, and pruritus.
Marine wounds can be infected with routine skin flora, such as Staphylococcus and Streptococcus species, along with bacteria unique to the marine environment. The most serious halophilic organism is the gram-negative bacillus Vibrio, which can cause rapid infections marked by pain, swelling, hemorrhagic bullae, vasculitis, and even necrotizing fasciitis and sepsis. Immunosuppressed patients, particularly those with liver disease, are susceptible to sepsis and death (up to 60%) from Vibrio vulnificus. Another bacterium, Erysipelothrix rhusiopathiae, implicated in fish-handler's disease, can cause painful, marginating plaques after cutaneous puncture wounds. The unique marine bacterium Mycobacterium marinum, an acid-fast bacillus, can cause a chronic cutaneous granuloma 3 to 4 weeks after exposure.
Numerous invertebrate and vertebrate marine species are venomous. The invertebrates belong to five phyla: Cnidaria, Porifera, Echinodermata, Annelida, and Mollusca.
The four classes of Cnidaria all share stinging cells, known as nematocysts, which deliver venom subcutaneously when stimulated. The most common effect is local pain, swelling, pruritus, urticaria, and even blistering and necrosis in severe cases. Some can cause systemic reactions due to toxic effects. The Hydrozoans include hydroids, Millepora (fire corals), and Physalia (Portuguese man-of-war). The latter causes a linear erythematous eruption and rarely can cause respiratory arrest, possibly from anaphylaxis. In addition to local tissue injury, the Scyphozoans (true jellyfish) include Atlantic Ocean larval forms that can cause a persistent dermatitis under bathing suits lasting days after exposure (Seabather's eruption). The Cubozoans (box jellyfish), in particular Chironex fleckeri in Australia and Chiropsalmus in the Gulf of Mexico, can cause a cardiotoxic death after severe stings. A Hawaiian box jellyfish, Carybdea, has been implicated in painful stings but no deaths. Another Australian box jellyfish, Carukia barnesi, can cause Irukandji's syndrome, characterized by diffuse pain, hypertension, tachycardia, diaphoresis, and even pulmonary edema. The most innocuous Cnidaria are the anthozoans (anemones) that occasionally cause a mild local reaction.
Porifera (the sponges) can produce a stinging, pruritic dermatitis. Spicules of silica or calcium carbonate can become embedded in the skin along with toxic secretions from the sponge. Echinodermata include sea urchins and sea stars. Sea urchin spines produce immediate pain with trauma; some contain venom that leads to erythema and swelling. Retained spines can lead to infection and granuloma formation. The crown-of-thorns sea star, Acanthaster planci, ...