Jellyfish are sea creatures. They have nearly see-through bodies with long, finger-like structures called tentacles. Stinging cells inside the tentacles can hurt you if you come in contact with them. Some stings can cause serious harm.
This article is for information only. DO NOT use it to treat or manage a jellyfish sting. If you or someone you are with is stung, call your local emergency number (such as 911), or your local poison center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States.
Types of jellyfish include:
- Lion's mane (Cyanea capillata)
- Portuguese man-of-war (Physalia physalis)
- Sea nettle (Chrysaora quinquecirrha), one of the most common jellyfish found along the Atlantic and Gulf coasts
- Sea wasp (Chironex fleckeri, Chiropsalmus quadrigatus), also known as box jellyfish, found near the coasts of northern Australia and the Philippines
There are also other types of jellyfish.
Symptoms of stings from different types of jellyfish are:
- Breathing difficulty
- Muscle cramps
- Skin burning and blistering (severe)
- Abdominal pain
- Changes in pulse
- Chest pain
- Muscle pain and muscle spasms
- Numbness and weakness
- Pain in the arms or legs
- Raised red spot where stung
- Runny nose and watery eyes
- Swallowing difficulty
- Mild skin rash (with mild stings)
- Muscle cramps and breathing difficulty (from a lot of contact)
Sea wasp or box jellyfish
- Breathing difficulty
- Nausea and vomiting
- Severe pain and swelling
- Slow heartbeat
- Skin tissue death
Seek medical help right away.
If you know for sure that the person has been stung by a Portuguese man-of-war or sea nettle, wash with salt water (ocean water is okay, but make sure you DO NOT get sand in the wound). Protect the affected area, if possible. Soak the area with a solution made of 1/2 vinegar and 1/2 water for about 30 minutes. This helps remove the tentacles. Rinse the area and then soak again with more of the vinegar-water solution.
Another way to remove tentacles is to apply shaving cream or a paste made from water and flour. Then, scrape the area with a dull edge, such as a credit card.
After removing the tentacles, apply a cream containing a painkiller, an antihistamine, or a steroid such as cortisone cream.
Before Calling Emergency
Have this information ready:
- Person's age, weight, and condition
- Type of jellyfish, if possible
- Time the person was stung
Your local poison center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States. They will give you further instructions.
This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.
What to Expect at the Emergency Room
The health care provider will measure and monitor the person's vital signs, including temperature, pulse, breathing rate, and blood pressure. Symptoms will be treated. The person may receive:
- Antivenin, a medicine to reverse the effects of the venom (for sea wasp stings)
- Blood and urine tests
- Breathing support, including oxygen, tube through the mouth into the throat, and breathing machine
- Chest x-ray
- EKG (electrocardiogram, or heart tracing)
- Fluids through a vein (by IV)
- Medicine to treat symptoms
Portuguese man-of-war and sea nettle stings are rarely deadly. Sea wasp stings can kill a person within minutes.
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Otten EJ. Venomous animal injuries. In: Marx JA, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 62.
Thornton S, Clark RF. Marine food-borne poisoning, envenomation, and traumatic injuries. In: Adams JG, ed. Emergency Medicine. 2nd ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 142.
Reviewed By: Jacob L. Heller, MD, MHA, Emergency Medicine, Virginia Mason Medical Center, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.