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A teenage girl returning from spring break
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A teenage girl went to Florida for spring break. When she emerged from the water one day, she felt pain on her lower leg and noted an eruption. A few weeks later, she presented with this clinical picture (Figure 1).
Think you know the diagnosis? Click to the next page to find out.
Answer
The diagnosis is a jellyfish sting.
Jellyfish, part of the phylum Cnidaria, are found throughout the world. They frequent warm ocean waters and often pose a threat to human swimmers. There are several types of jellyfish, ranging from harmless to deadly, depending on regional location. Common jellyfish in Florida include the cannonball jellyfish (Stomolophus meleagris), the moon jellyfish (Aurelia aurita), the sea nettle (Chrysaora quinquecirrha), multiple types of box jellyfish and the Portuguese man-of-war (Physalia physalis), which is not a true jellyfish.
It is difficult to estimate the incidence of jellyfish stings. A case series reviewed jellyfish stings called to Texas poison centers from 1998 to 2004 and reported 423 cases. However, because there is no mandatory reporting, this is likely an underestimate of the total number of jellyfish stings over that period. This patient noted that more than 300 stings were reported on the beach she was visiting that season alone!
Jellyfish contain nematocysts, the stinging or envenomation mechanism used for both attack and defense. The nematocysts are located on the tentacles of the jellyfish as well as on the inferior surface of their body. When the nematocysts come into contact with human skin, their venom is injected into the tissue. The nematocysts may even detach from the jellyfish, allowing recurrent stinging that can last weeks to months. The venom contains catecholamines and histamines whose antigenic and toxic properties can lead to skin necrosis, allergic reactions and cardiopulmonary toxicity.
Envenomation can cause an immediate local and systemic reaction due to a type 1 hypersensitivity response. The local reaction typically causes a burning sensation followed by the formation of erythematous linear papules or wheals, which may fade or evolve to erythematous papulovesicular lesions or necrosis. Delayed skin changes can include scarring, dyspigmentation and atrophy. Possible systemic effects include gastrointestinal symptoms such as nausea, vomiting or diarrhea, neurological symptoms including headache, malaise, confusion, paresthesias, paralysis and seizures, and musculoskeletal symptoms such as myalgias and muscle spasm. Most worrisome are cardiopulmonary effects, which include dysrhythmias, hypotension, anaphylaxis and respiratory distress or failure.
Other effects of jellyfish stings include the seabather’s eruption and Irukandji syndrome. Seabather’s eruption is reported in North America following entrapment of jellyfish or sea anemone larvae beneath a bathing suit. The nematocysts are then activated by pressure, contact with skin or fresh water. The resulting rash is described as pruritic red papules or wheals that may coalesce, similar in appearance to insect bites that last for three to seven days or in severe cases up to six weeks. Systemic symptoms may include headache, vomiting, fever and chills. Certain individuals are at risk for recurrence if they develop IgG antibodies against the jellyfish antigen.
Irukandji syndrome is caused by the Irukandji (Carukia barnesi) box jellyfish as well as other jellyfish found in tropical Australia. The syndrome is thought to be due to catecholamine release and involves pain, often severe hypertension and gastrointestinal symptoms. Most severely, there is a risk for cardiac failure, pulmonary edema or death.
Treatment of jellyfish envenomation is based on three principles: decontamination, removal and pain control. Goals of decontamination include immobilizing the affected area to decrease the risk of spreading the venom and washing off remaining nematocysts. Decontamination can be accomplished with sea water, alcohol, vinegar, baking soda, dilute ammonia or meat tenderizer. Urine is not recommended and can actually trigger nematocysts to release more venom.
Decontamination protocols vary depending on the type of jellyfish. For example, Chironex fleckeri, a dangerous jellyfish found in the South Pacific, will respond to vinegar but may also require anti-venom for more severe reactions. It was reported that the Carybdea alata jellyfish found in Hawaii responds well to fresh water at high temperatures rather than sea water. Most jellyfish stings, however, can be initially treated with seawater or one of the household products mentioned above.
Once decontaminated, the jellyfish can be removed by a gloved hand or, additionally, a slurry or paste can be made and scraped off with a knife, razor or shell if on the beach. Recommended pastes include shaving cream, baking soda, flour or sand mixed with sea water.
Pain control can be achieved with over-the-counter analgesics, prescription narcotics, hot water immersion (jellyfish protein toxins are heat labile) and topical therapy such as anesthetic salve or steroids. Some patients may require antihistamines or oral steroids for allergic symptoms. Finally, tetanus prophylaxis should be considered if the skin is broken.
Jellyfish remain a common threat to swimmers in oceans worldwide. Recognizing both the dermatologic and systemic manifestations of these stings allows for prompt decontamination and treatment. Physicians should counsel swimmers on jellyfish sting prevention. This includes wearing protective suits or applying a jellyfish sting inhibitor lotion prepared synthetically from the skin of clown fish, the only known animal to remain unharmed by nematocysts.
For more information:
- Marissa J. Perman, MD, is a PL-III resident at Cincinnati Children’s Hospital Medical Center.
- McRee, D. How to be safe from sharks, jellyfish, stingrays, rip currents. Beachhunter.net website. http://www.beachhunter.net. Published 2005. Accessed Oct. 16, 2007.
- Forrester MB. Epidemiology of jellyfish stings reported to poison centers in Texas. Hum Exp Toxicol. 2006;25:183-186.
- Habif, TP. Clinical Dermatology: A Color Guide to Diagnosis and Therapy. Philadelphia: Mosby; 2004:539-542.
- Singletary EM, Rochman AS, Bodmer JC, Holstege CP. Envenomations. Med Clin North Am. 2005;89:1195-1224.
- Ulrich H, Landthaler M, Vogt T. Granulomatous jellyfish dermatitis. J Dtsch Dermatol Ges. 2007;5:493-495.
- Junghanss T, Bodio M. Medically important venomous animals: biology, prevention, first aid, and clinical management. Clin Infect Dis. 2006;43:1309-1317.
- Bailey PM, Little M, Jelinek GA, Wilce JA. Jellyfish envenoming syndromes: unknown toxic mechanisms and unproven therapies. Med J Aust. 2003;178:34-37.
- Curtin, C. Fact or fiction?: Urinating on a jellyfish sting is an effective treatment. http://www.sciam.com. Published Jan. 4, 2007. Accessed Oct. 16, 2007.
- Yoshimoto CM. Jellyfish species distinction has treatment implications. Am Fam Physician. 2006;73:391.
- Uri S, Marina G, Liubov G. Severe delayed cutaneous reaction due to Mediterranean jellyfish (Rhopilema nomadica) envenomation. Contact Dermatitis. 2005;52:282-283.
- Kimball AB, Arambula KZ, Stauffer AR, et al. Efficacy of a jellyfish sting inhibitor in preventing jellyfish stings in normal volunteers. Wilderness Environ Med. 2004;15:102-108.
Spot the Rash is a monthly case study featured in Infectious Diseases in Children designed to test your skills in pediatric dermatology issues.