Jellyfish stings

Published on 18/03/2015 by admin

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Last modified 18/03/2015

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Jellyfish stings

Christopher Sladden, Jamie Seymour and Mike Sladden

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports

Jellyfish are members of the phylum Cnidaria, which consists of five classes: Cubozoa (box jellyfish), Hydrozoa (Portuguese man-of-war), Schyphozoa (true jellyfish), Staurozoa (staromedusans), and Anthozoans (corals). They are found in every ocean and some fresh water, from the surface to the depths of the seas. They often consist of a bell shaped body, ranging from 1 millimeter to over 2 meters in diameter, with tentacles up to 30 meters in length. Many have complex life cycles, usually with both a sexual and an asexual stage, often with a sessile polyp stage and a motile medusal stage.

Jellyfish envenomings can occur during recreational and commercial pursuits, both in the water and when encountering living or dead animals on the shore. Jellyfish sting their prey using nematocysts, stinging structures located in specialized cells called cnidocytes. Contact with a jellyfish tentacle can trigger millions of nematocysts to pierce the skin and inject venom. Those providing care to sting victims should avoid being stung by adherent tentacles on the victim; however, the risk of the carer being envenomed is minimal.

The severity of jellyfish stings depends on the species of jellyfish involved, its age and geographic location, the location of the nematocysts involved (bell or tentacle) and factors such as patient age and general health, amount of skin involved, and number of nematocysts triggered. Understanding the complexity of jellyfish venom is still in its infancy.

Most jellyfish stings are self-limiting, causing localized pain and skin lesions. However, symptoms can range from local discomfort, to severe pain, through to cardiovascular collapse and death. Immediate management of jellyfish stings occurs at the beach with first aid and resuscitation, and then if needed in hospital. Immediate cutaneous reactions include wheals, blisters, and angioedema. Dermatologists are most likely to become involved later to manage the delayed sequelae of jellyfish stings.

In this chapter we will discuss the most important type of jellyfish stings, the different symptoms and management of these stings, as well as strategies for prevention of jellyfish stings.

Clinical features

Major box jellyfish (Chironex fleckeri)

Chironex fleckeri are only found in northern Australian waters. However, several other species of chiropdropids (or multi-tentacled box jellyfish) found throughout non-Australian tropical realms are also capable of inflicting life threatening envenomings. Stings can cause large welts, severe pain, and loss of consciousness. Victims can drown before reaching shore. Skin necrosis can occur with severe stings. Severe envenomation is rare but can cause cardiovascular collapse. Many deaths occur within minutes of envenomation, when the antivenom is often unavailable.

Irukandji jellyfish (Carukia barnesi)

Irukandji syndrome is a poorly defined set of symptoms occurring after envenoming by certain species of ‘box jellyfish’. The initial sting is often barely noticed and symptoms develop after 20–30 minutes. Manifestations include headaches, severe pain, nausea, vomiting, pulmonary edema, hypertension, and cardiac dysfunction, sometimes resulting in death. The variation in symptoms has resulted in a myriad of treatments though none have been established as definitive. Although the syndrome is well documented in coastal northern Australia, it appears that Irukandji syndrome is an increasing marine problem worldwide.

Bluebottles or Portuguese man-of-war (Physalia species)

Bluebottle stings cause immediate, intense pain and a linear red eruption at the sting site but rarely systemic effects. However, the Portuguese man-of-war (Physalia physalis), found in the Atlantic, Pacific, and Indian Oceans, deserves special attention because it is potentially lethal.

True jellyfish (Schyphozoans)

The majority of jellyfish envenomings throughout the world occur from the schyphozoans. Symptoms may range from mild irritation through to significant welts on envenomed victim which may result in skin necrosis in some instances. Life threatening complications from these envenomings are rare.

Seabather’s eruption

This is an acute dermatitis caused by larvae of thimble jellyfish (Linuche unguiculate) and sea anemone (Edwardsiella lineata). It has been described in Florida, Bahamas, Bermuda, South-East Asia, Brazil, and New York. The rash, usually confined to underneath the bathing suit, is a highly pruritic and erythematous papular eruption. Symptoms usually begin hours to 15 days after exposure.

Cutaneous manifestations of jellyfish stings

Immediate cutaneous reactions include wheals and blisters at the site of the sting. In more severe stings, partial or full thickness skin necrosis can occur. Delayed, persistent or recurrent eruptions have been reported at the initial envenomation site, taking the form of erythema, urticarial lesions, papules, and plaques. Delayed hypersensitivity reactions occur infrequently. Other sequelae include dermatitis, secondary infection, post-inflammatory hyperpigmentation and scarring, and erythema nodosum.

Management Strategy

First-line therapies

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Prevention of jellyfish stings
Stinger suits worn next to the skin reduce contact with jellyfish tentacles	E
Stinger nets to provide physical barrier between jellyfish and swimmers (NB: these are only effective on jellyfish which are larger than the net mesh size)	E
Proprietary Safe Sea cream (NB: this treatment may cause the discharge of more nematocysts in some species)	A

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