What does a jellyfish sting look like?

Jellyfish stings leave a distinctive print of tentacles leaving narrow trail marks. Jellyfish have thousands of stinging cells, known as nematocysts, on their tentacles. The nematocysts release toxins when you bump or brush against them, causing skin irritation, pain, and blisters.

How do you treat a jellyfish sting?

Treating a jellyfish sting is a two-step process. First, you want to remove any visible stingers. Do not scrape off stingers. Instead, carefully remove stingers using tweezers. Next, soak the sting in hot water to draw out the venom. The water should feel hot but not scalding. Soak the injured skin for 20 to 45 minutes.

How long does the pain from a jellyfish sting last?

A jellyfish sting causes severe pain and burning that lasts about an hour or two. As the pain subsides, it typically begins to itch. The itching can last for a week.

Gallery of Jellyfish Sting Pictures

Jellyfish stings are a common cause of emergency room visits in tropical coastal areas. Jellyfish have tentacles with thousands of stinging cells called nematocysts. They fire toxins when you bump or brush against them.

These stings cause pain, blisters, and skin necrosis or cell death. People who've been stung may have weakness, fever, chills, muscle spasms, nausea, and vomiting. In rare cases, some types of jellyfish, such as the Chironex fleckeri box jellyfish in Australia, can cause paralysis and death.

This gallery shows what different stings can look like. It also explains how they should (and shouldn't) be treated.

Jellyfish Sting on Knee

Jellyfish stings have a distinctive look. The sting often leaves a "print" of the tentacle. You may see red, brown, or purple track marks on the skin. Along with the marks, you may feel:

Burning, prickling, or stinging
Itching
Swelling
A throbbing pain shooting up a leg or arm

Seek emergency care if you have signs of anaphylaxis. Signs include shortness of breath, hives, rapid heartbeat, nausea, confusion, and swelling of the face, tongue, or throat. This condition is a medical emergency which can lead to death.

Jellyfish stings can usually be diagnosed by how they look. They are often mistaken for stings from other sea creatures, including:

Portuguese man o' wars
Blue bottles
Puffer fish
Sea anemones

Jellyfish Sting on Knee After 2 Days

Healing Bumps from the Tentacle's Path — Erin/Flickr Creative Commons

Two days after a jellyfish sting, the skin will have started to heal. It will still show faint tentacle marks. If you have a hypersensitivity reaction, you may notice a rash or hives. These can usually be treated with oral antihistamines or corticosteroids. They're available over the counter (OTC).

Tylenol (acetaminophen) or OTC nonsteroidal anti-inflammatory drugs (NSAIDs) like Advil (ibuprofen) or Aleve (naproxen) can ease pain.

Jellyfish Sting on the Torso

Inflammation Shows the Shadow of the Stinging Jellyfish — Pete & Brook

If a jellyfish tentacle touches you, thousands of nematocysts can pierce your skin and inject toxins. Depending on the species and the number of stings, your reaction may range from mild to severe. If there are many stings, venom can build up in your blood vessels. That can cause patchy redness, swelling, and burning.

The first step in treating the sting is to remove any parts of the tentacle still attached to the skin—but not with your bare hands. Even if the tentacle is no longer attached to the creature, it can keep injecting toxins. The best ways to remove a tentacle are with gloves, a brush, or the edge of a credit card.

Jellyfish Sting on Arm

A Jellyfish Attacks in an Exotic Location — Kate Nevens/Flickr Creative Commons

There is some debate about the best way to treat a jellyfish sting. In one camp, there are those who insist that distilled white vinegar will "neutralize" the toxins.

Others insist that the body part should be soaked for 20 to 45 minutes in hot water 110 to 113 F (43 to 45 C) to draw out the toxins. If there are any stingers still in the skin, you can pluck them out with tweezers.

Some people use all of these methods, soaking the skin in vinegar for 30 seconds before removing the remaining stingers. Then they follow with soaking for 20 to 40 minutes in hot but not scalding water.

Using a cold compress after the soak may help ease the pain and inflammation.

Man-O-War Sting

Oh! Man-O-War this Looks Painful! — Portuguese man o' war sting.
Simon Tonge/Flickr Creative Commons

You can tell jellyfish stings from other stings by the narrow trail of tentacle marks they leave. Other jellyfish-like creatures, such as the Portuguese man o' war, tend to leave wider marks on the skin. The areas of redness, swelling, inflammation are also larger.

Pufferfish stings are more spread out. The marks are irregular with a cluster of raised sores. Anemone stings are similar, but more tightly clustered. They sometimes develop blister-like sores that ooze.

Learning the difference between these types of stings can help you get the right treatment. Some stings, like those from a man o' war, can be severe.

While man o' war stings can cause extreme pain, they are rarely deadly. Far more serious is the box jellyfish of Australia. They have caused eight deaths since 2000 with two in 2016 alone.

Jellyfish Sting to the Neck

More than Jellyfish Can Sting in the Ocean — Mat Honan

Jellyfish stings to the face or head usually don't leave scars if treated properly. If you're stung near the eye, flush the eye with lots of water. Go to the nearest emergency room or call 911 if you can't drive yourself.

An ophthalmologist or eye doctor will need to remove any stingers and assess the injury. You may need oral antibiotics to prevent infection and reduce the risk of eye damage.

Sea Anemone Sting

Whatever the cause of the sting, do not:

Rinse a sting with urine
Apply meat tenderizer
Apply alcohol or ammonia
Apply pressure bandages
Rub the skin with sand
Rub the skin with seaweed
Soak the skin with cool, fresh water or sea water, which can release even more venom

Jellyfish Sting on the Feet

Jellyfish stings on feet — bobafred/Flickr Creative Common

Most jellyfish stings don't need medical care. They can often be treated at home. Think about these factors as you decide how severe a sting may be:

The type of jellyfish
The number of stings
The amount of skin affected
The length of time you were exposed
Your age, general health, and medical conditions such as heart problems or a history of anaphylaxis

Young children are smaller and more prone to more serious reactions. They should always be seen by a doctor. Reactions may come on quickly or several hours after the sting.

Summary

Jellyfish stings involve thousands of jabs, each of which releases toxins. They can cause pain, swelling, redness, and itching. For some people, they can also cause an allergic reaction that can be life-threatening.

To tell a jellyfish sting from other sea creature stings, look for narrow trails of tentacle marks. A wide trail or one with random clusters is likely to be the sting of a different creature.

You'll need to remove any stingers left in the skin. If the sting isn't severe, it can probably be treated at home with distilled white vinegar, a hot water soak, or both. If you start to have breathing problems, a racing heartbeat, or swelling, it's time to go to an urgent care clinic or the emergency room.

Frequently Asked Questions

What does a jellyfish sting look like?

Jellyfish stings leave a distinctive print of tentacles leaving narrow trail marks. Jellyfish have thousands of stinging cells, known as nematocysts, on their tentacles. The nematocysts release toxins when you bump or brush against them, causing skin irritation, pain, and blisters.
How do you treat a jellyfish sting?

Treating a jellyfish sting is a two-step process. First, you want to remove any visible stingers. Do not scrape off stingers. Instead, carefully remove stingers using tweezers.
Next, soak the sting in hot water to draw out the venom. The water should feel hot but not scalding. Soak the injured skin for 20 to 45 minutes.
How long does the pain from a jellyfish sting last?

A jellyfish sting causes severe pain and burning that lasts about an hour or two. As the pain subsides, it typically begins to itch. The itching can last for a week.

9 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Cegolon L, Heymann WC, Lange JH, Mastrangelo G. Jellyfish stings and their management: a review. Mar Drugs. 2013;11(2):523-550. doi:10.3390/md11020523
National Ocean Service. What is the most venomous marine animal?
Imamura K, Tsuruta D, Tsuchisaka A, et al. Anaphylaxis caused by ingestion of jellyfish. Eur J Dermatol. 2013;23(3):392-395. doi:10.1684/ejd.2013.2030
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Thaikruea L, Siriariyaporn P. The magnitude of severe box jellyfish cases on Koh Samui and Koh Pha-ngan in the Gulf of Thailand. BMC Res Notes. 2016;9:108. doi:10.1186/s13104-016-1931-8
Madio B, King GF, Undheim EAB. Sea anemone toxins: A structural overview. Mar Drugs. 2019;17(6):325. doi:10.3390/md17060325
Tiemensma M, Currie BJ, Byard RW. Fatal jellyfish envenoming-Pediatric and geographic vulnerabilities. J Forensic Sci. 2021;66(5):2006-2009. doi:10.1111/1556-4029.14753

Additional Reading

Gershwin, L.; Condie, S.; Mansbridge, J. et al. Dangerous jellyfish blooms are predictable. J Royal Soc Interface. 2014;11(96):20131168. DOI: 10.1098/rsif.2013.1168.
Ping, J. and Onizuka, N. Epidemiology of Jellyfish Stings Presented to an American Urban Emergency Department. Hawaii Med J. 2011;70(10):217-9.

By Rod Brouhard, EMT-P
Rod Brouhard is an emergency medical technician paramedic (EMT-P), journalist, educator, and advocate for emergency medical service providers and patients.

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