What to Do (and Not to Do) If You're Stung By a Jellyfish

Jellyfish stings come from cells called nematocysts that are found on the long tentacles that trail the bell-shaped jellyfish and, in some species, are on the bell itself. These cells inject a protein-based venom.

Severe allergic reactions are the most dangerous reaction to most jellyfish stings. However, some species have strong enough venom to kill you even if you're not allergic to them.

Jellyfish Sting
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Symptoms

Jellyfish use their stings to subdue their prey. Their tentacles are armed with thousands of nematocysts that can pierce the skin and inject venom. Depending on the species and the venom dose, a sting can cause reactions ranging from mild to life-threatening.

Common

Jellyfish stings are common with an estimated 150 million incidences per year. Most are mild and readily treatable at home.

The symptoms of a mild jellyfish bite may include:

  • A stinging, prickling, or burning pain
  • Red or purplish "track marks" along the route of contact with the tentacle
  • Local itching and swelling
  • Throbbing pain radiating up an arm or leg
  • Rash (occasionally)

Severe

There is a lot still unknown about the causes of a severe reaction to jellyfish stings, in part because there are over 2,000 species of jellyfish around the world.

While most jellyfish stings are relatively mild, some can be severe and even life-threatening. This risk varies not only by the jellyfish species and venom dose but also by the individual's response to the venom.

In some cases, the symptoms may be caused by the venom itself (typically a neurotoxic reaction affecting the heart and respiration). In others, a sting may provoke a severe hypersensitive reaction known as anaphylaxis in which the immune system over-reacts the venom. Both may be involved and are often difficult to tell apart.

In most cases, a severe reaction will occur immediately or soon after the sting. However, if anaphylaxis is involved, reactions have been known to be delayed for days and even weeks.

Symptoms of a severe jellyfish sting include:

  • Numbness or tingling
  • Shortness of breath
  • Wheezing
  • Chest pain
  • Muscle cramps
  • Hives
  • Blistering skin
  • Nausea or vomiting
  • Difficulty swallowing
  • Rapid heartbeat
  • Heart palpations
  • Dizziness or fainting

Irrespective of whether the effects are toxic or hypersensitive, symptoms like these require immediate medical care. Call 911 or have someone rush you to the nearest emergency care.

If left untreated, anaphylaxis can lead to shock, coma, heart or respiratory failure, or death.

2

Treatment

The rapid treatment of jellyfish stings can reduce pain, keep systemic symptoms from getting worse, and lower the risk of complications (including infections).

Once first aid is delivered, medications can help alleviate pain and swelling. Severe reactions need to be treated in a hospital.

First Aid

There are three steps commonly recommended for the first aid treatment of a jellyfish sting:

  1. Rinse: Rinse away the tentacles using hot water if possible. If hot water isn't available, use salt water rather than fresh. Freshwater may worsen the pain.
  2. Remove tentacles: Peel off any remaining tentacles with a gloved hand or tweezers. Avoid using bare hands as you risk getting stung again.
  3. Take a hot bath: This can help extract some of the venom from the wound. The general rule is to bathe at the hottest possible temperature (at least 108 degrees F and up to 140 degrees F if you are able to tolerate it.

OTC Medications

Once you have removed the tentacles and immersed the wound in hot water, there are things you can do to control pain and promote healing. Over-the-counter (OTC) medications include:

An ice pack can also relieve pain and swelling, but be sure to place a cloth between the skin and ice pack and to ice the skin for no longer than 15 minutes to prevent frostbite.

Treatment of Anaphylaxis

Anaphylaxis is treated as a medical emergency in a hospital. The treatment starts with an injection of epinephrine (adrenaline) that helps relax the airways so you can breathe easier while tightening blood vessels to increase blood pressure. This latter effect helps reduce the risk of shock.

Afterward, you may be given oxygen, intravenous (IV) fluids, and medications like cortisone, albuterol, and antihistamines to improve breathing and/or halt the allergic response.

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What Not to Do

There are a lot of myths and misconceptions about how you should treat jellyfish stings. Few of these homespun remedies have any research to support their use and may cause more harm than good.

For example, some people recommend rinsing a jellyfish sting with white vinegar to relieve pain, but the evidence is split on whether this actually helps. The benefits appear to differ by species.

A 2017 study of the lion's mane jellyfish suggests that rinsing a sting with seawater may actually increase the release of venom, while rinsing with vinegar has no such effect. By contrast, rinsing a bluebottle jellyfish sting with vinegar often makes the sting worse.

To Pee or Not to Pee?

Despite what some people may tell you, peeing on a jellyfish sting may make the pain worse and will do little if anything to "neutralize" the venom. Moreover, peeing on a tentacle may cause it to contract, injecting more venom into the skin.

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Avoiding Jellyfish Stings

Avoiding jellyfish stings is undoubtedly a better strategy than treating jellyfish stings. There are several things you can do to better protect yourself:

  • Prepare: Before venturing out into the sea, learn which species of jellyfish are common in the area, how dangerous they are, and what to do in the event of a sting.
  • Plan: Jellyfish are attracted to warmer water and will often appear seasonally as the tidal flow changes. Contact local authorities or lifeguards about when jellyfish season is at your destination.
  • Wear a protective suit: If you are visiting an area where jellyfish are common, you can protect yourself by getting a "skin suit" (also known as a "stinger suit") available at many diver shops. They are lightweight but act as an effective barrier if you brush up against a jellyfish.
  • Get a jellyfish repellent: If you are really worried about jellyfish, there are some commercially available lotions that are said to repel jellyfish. Although it is unclear how effective they are, many customers swear by them. There are even suntan lotions that contain jellyfish repellent.
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Frequently Asked Questions

How do you treat a jellyfish sting?

Despite what some people may tell you, peeing on a jellyfish sting is unlikely to help. Ideally, you would treat a jellyfish sting by:

  1. Rinsing any tentacles remaining in the skin with hot water
  2. Removing the tentacles with a gloved hand or tweezers
  3. Soaking the affected body part in hot water, ideally at around 108 degrees F and up 140 degrees F if you can tolerate it

What does a jellyfish sting look like?

Jellyfish stings vary in size depending on the species. They typically cause raised bumps surrounded by reddish or purplish skin where the stingers have punctured the skin. The bumps are often laid out in "tracks" where the tentacle has come into contact with the skin.

How do jellyfish sting?

Jellyfish tentacles are covered with microscopic stingers called nematocysts. Each nematocyst is comprised of a tiny capsule of venom and a coiled tube topped with a puncturing barb. When you brush against a jellyfish, sensors on the tentacle will cause the capsule to contract and the coiled tube to extend, releasing the venom.

What does a jellyfish sting feel like?

A jellyfish sting is commonly described as being sharp, burning, prickling, or stinging. Oftentimes, the sting will be accompanied by a throbbing pain that radiates upward and outward on the arm, leg, or torso.

How long does a jellyfish sting last?

The duration and severity of a jellyfish sting can vary by species. Stings from small bluebottle jellyfish may last for one hour. A sting from the Australian sea wasp (Chironex fleckeri)—described by some as the most lethal jellyfish in the world—can be deadly, especially in small children.

A Word From Verywell

Many of the homespun remedies for jellyfish stings have been passed down through generations or by word of mouth. Few are supported by research, and even experts are hard-pressed to offer a "one-size-fits-all" solution for all jellyfish stings.

Because the treatment recommendations can differ by species, it pays to know what kinds of jellyfish are common in the area you are visiting and to research how they are treated. In the event of a sting, you can call Poison Control at 800-222-1222 for immediate advice on what to do.

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