Jellyfish stings

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Definition

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 the National Poison Control Center at 1-800-222-1222.

Poisonous Ingredient

Jellyfish venom

Where Found

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

Symptoms of stings from different types of jellyfish are:

Lion's mane

  • Breathing difficulty
  • Muscle cramps
  • Skin burning and blistering (severe)

Portuguese man-of-war

  • Abdominal pain
  • Changes in pulse
  • Chest pain
  • Collapse
  • Headache
  • 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
  • Sweating

Sea nettle

  • 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

Home Care

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

Poison Control

The National Poison Control Center (1-800-222-1222) can be called from anywhere in the United States. This national hotline number will let you talk to experts in poisoning. 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

Outlook (Prognosis)

Portuguese man-of-war and sea nettle stings are rarely deadly. Sea wasp stings can kill a person within minutes.

References

Auerbach, PS. Envenomation by aquatic invertebrates. In: Auerbach PS, ed. Wilderness Medicine. 6th ed. Philadelphia, PA. Elsevier Mosby; 2011:chap 80.

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.

Version Info

  • Last reviewed on 7/13/2015
  • 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.

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