Jellyfish stings

Jellyfish is a kind of venomous marine creature with numerous cnidocytes containing venom on its tentacles. Jellyfish are transparent in sea water, and can hardly be seen by swimmers, so that there are numerous cases of stings.


Causes

On the tentacles of jellyfish, there are dense nematocysts composed of toxin-containing capsules and curved, tapered stingers. Once being stung, the toxins rich in serotonin, tetraamine, and histamine will enter the human skin from the nematocyst capsules through the stingers. The lethal mechanism of jellyfish is mainly anaphylactic shock caused by toxins (related to personal constitution), followed by direct toxicity.

Figure 1 jellyfish


Signs and Symptoms

Local symptoms

There are immediately burning, scratchiness, and tingling sensations after being stung, and linear erythema, papules gradually appear, resembling whipping scars. In patients with severe stings or allergic constitution, erythema, urticaria, vesicles, ecchymosis, and even epidermal necrosis occur, and unbearable pain, severe pruritus, and large area of flush may be present. Local symptoms generally last for 10 - 20 days, up to several months. In severe cases, there may be pigmentation, scars, and gangrene.

Video 1 skin lesions of jellyfish stings

Systemic symptoms

Systemic anaphylactoid reactions occur within minutes to hours after severe stings, and main manifestations include:

  • Skin and mucous membranes: initial chest tightness, skin itches, followed by urticaria and angioedema, mainly around the eyes, upper and lower lips, occasionally in the throat.
  • Respiratory system: cough, chest tightness, shortness of breath, dyspnea, frothy sputum, and acute respiratory distress syndrome, often accompanied by cough, asthma, and cyanosis.
  • Nervous system: headache, cold or heat sensation, dizziness, ataxia, spastic or flaccid paralysis, and delirium.
  • Circulatory system: arrhythmia, bradycardia, hypotension, and heart failure.
  • Motor system: diffuse myalgia, arthralgia, dorsalgia, muscle spasm, and abdominal rigidity.
  • Digestive system: nausea, vomiting, diarrhea, dysphagia, salivation, as well as abdominal cramps with vomiting and diarrhea.
  • Others: hemolysis, hepatorenal damage, conjunctivitis, chemosis, keratohelcosis, and lacrimation, also lower abdominal pain caused by contraction of uterine smooth muscle..

Anaphylactic shock

Anaphylactoid reactions can occur suddenly, often initially a sense of impending death, followed by one or more target organs involved.

Irukandji syndrome

Irukandji syndrome refers to the reaction after being stung by Irukandji jellyfish, and is characterized by headache, diaphoresis, nausea, severe pain in multiple sites, spasms in the extremities, facial burning sensation, tachycardia, and hypertension.

Delayed jellyfish envenomation syndrome

Multiple organ dysfunction occurs 2 - 48 hours after jellyfish stings.


Diagnosis

If there are a history of exposure to jellyfish and characteristic skin lesions, the condition can be diagnosed.


Treatment

The sting sites should be rinsed with sea water, and make sure to keep in mind do not use fresh water. Rescuers should wear gloves to avoid being stung. Rinse or wet compress with 5% - 10% sodium bicarbonate or saturated alum solution can be applied. Topical licorice lotion or glucocorticoid ointments can be considered.

Hospitalization may be required if there are severe reactions.

Antianaphylactic treatment and symptomatic treatment should be administered.

Epinephrine, glucocorticoids, bronchodilators can be considered if needed.