Some species of jellyfish, prevalent worldwide, can cause envenomation that results in symptoms ranging from mild to severe. Jellyfish sting can cause serious skin manifestations. The systemic involvement is possible too. The workup includes an urgent physical exam, a detailed history, and laboratory studies to assess for organ damage.
Jellyfish are found in every ocean and are prevalent in the tropics and northern Europe     . Of nearly 9000 species, only around 100 cause harm to humans  . Specifically, Physalia physalis , Chironex fleckeri , and Carukia barnesi are the three most toxic species. Jellyfish sting is a frequent event as it has been reported that 150 million incidents occur annually . There are as many as 800 incidents in some Pacific locations daily . Fortunately, most jellyfish stings result in recovery.
Depending on the type of species and the envenomation dose , effects can range from mild symptoms to rapid fatality   . Local symptoms and signs include pain, swelling, pruritus, and eventually necrosis at the site of an injection   . Purplish-brownish vesicles develop and may last anywhere from minutes to weeks.
Systemic findings, if present, include nausea, emesis, fever, malaise, headache, paresthesias, and muscular spasms  . Multiorgan effects reflect the involvement of gastrointestinal, cardiovascular, hematologic, neurologic, urinary, musculoskeletal, immunologic, and/or pulmonary systems  . Additionally, ophthalmologic manifestations can include conditions such as ulceration of the cornea, conjunctivitis, and swelling of the eyelids.
While the majority of cases are nontoxic, some lead to sequelae such as infection of the wound, acute kidney failure, hemolysis, rhabdomyolysis, pulmonary edema and respiratory distress, dangerous arrhythmias, and cardiopulmonary arrest    .
Vital signs changes may include tachycardia and alteration in blood pressure  . Furthermore, the sting site is characterized by tenderness, erythema, and edema . The color change and scarring may be permanent .
A detailed history should be elicited from the patients and/or witnesses if possible. The key questions should consist of details about the time of the sting, the onset and evolvement of the clinical features, the location of the incident, and identity of the organism. Very importantly, a physical exam must be performed and the patient should be immediately evaluated for the basic life support as well as for the evidence of local and systemic effects . Additionally, the clinician should eliminate the tentacles as much as possible  . Note that patients with anaphylaxis should be managed urgently and resuscitated promptly. Pain and wound care are also important to treat.
Individuals with severe manifestations should be assessed for organ damage with a complete blood count (CBC), complete metabolic panel (CMP) including renal and liver function tests, cardiac enzymes, thyroid function tests, and creatine phosphokinase. Additionally, urinalysis and arterial blood gases (ABG) should be performed.
Chest radiography is indicated for patients with respiratory distress.
Electrocardiogram (ECG) is useful for identifying arrhythmias. Finally, skin samples can be evaluated for the presence of nematocysts.