Box jellyfish stings

Delayed Allergic Reaction

Some stings can cause an allergic reaction that doesn’t appear for a week or two or even longer. It can cause a rash, blisters, or other kinds of skin irritations.

Your healthcare provider can give you topical or oral treatments to address the condition.


A box jellyfish’s tentacles can leave permanent scars, including keloids, which are raised areas of scar tissue. There may be changes in skin color, and lichenification, in which the skin becomes thick and leathery in appearance. In some cases, areas of the skin die.

Box jellyfish stings


Reactions to box jellyfish stings can be immediate or delayed by several days or even weeks. Complications may include the following.

Irukandji Syndrome

Some box jellyfish stings cause Irukandji syndrome, a group of symptoms that begin 20–30 minutes after the sting and progress over a few days.

 The syndrome is not typically fatal, but it can make you seriously ill, and some people do die from it.

Symptoms include:

  • Pain
  • Muscle cramping and spasms
  • Sweating
  • Shaking
  • Nausea and vomiting
  • Rapid heart rate
  • High blood pressure

In very serious cases, a person may experience cardiogenic shock or a pulmonary edema.

Irukandji syndrome often requires hospitalization, so if you have been stung by a jellyfish, pay close attention to symptoms that may arise sometime afterward.

Box jellyfish stings

What Not to Do

It’s important to know what you shouldn’t do as well as what you should do in the event of a box jellyfish sting, such as:

  • Do not touch or press on the site of the sting.
  • Do not rinse with fresh water, alcohol, or ammonia (urine), which could spread the venom.
  • Do not ignore it and wait for the pain to go away. Serious complications can still arise hours or days after a sting.
Box jellyfish stings


It’s best to treat any painful jellyfish sting rapidly and seriously, even if you don’t know what kind stung you. While some kill within minutes, other box jellyfish stings can lead to death in four to 18 hours.

If you witness a box jellyfish sting, immediately do the following:

  • Help the person exit the water and try to keep them calm.
  • Call 911 or other emergency medical personnel.
  • Put hot water, vinegar, or baking soda on the sting, if available. If not, put salt water on it. That will help stop the release of venom. Avoid fresh water.
  • Remove any tentacles that you see in the skin. Do this with a knife, tweezers, or some other sharp object. Only use your hands if covered with rubber gloves—never use your bare hands.
  • If the person is unconscious, start CPR if you know how to do it.

Medical professionals can perform resuscitation, which may keep the person alive until the reaction to the venom weakens.

Experts in Australia developed an antidote to the most deadly form of box jellyfish sting, which works in about 15 minutes, but getting it to victims in time is a challenge.

Box jellyfish stings


Box jellyfish stings are extremely painful. Some symptoms can arise hours to weeks after a sting, but the most deadly appear immediately. They include:

  • Red whip-shaped lesions on the skin called “wheals”
  • Blistering and burning at the site of the sting
  • Severe abdominal pain
  • Chest pain
  • Shock
  • Fever or chills
  • Muscle spasms
  • Sweating
  • Nausea or vomiting

When a sting is fatal, death is usually due to cardiac arrest. Experts think the poison affects the heart directly.

Box jellyfish stings

Box Jellyfish Stings

There are more than 40 species of box jellyfish, and eight of them are deadly.1

 Though most box jellyfish stings are not life-threatening, some can kill in as little as five minutes. Quick treatment is essential to saving life.

This article describes the symptoms, treatment, and complications of box jellyfish stings.

Box jellyfish underwater