Jellyfish stings: MedlinePlus Medical Encyclopedia

P 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.
P 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.

T Poisonous Ingredient
P Jellyfish venom

T Where Found
P Types of potentially harmful jellyfish include:
- Lion's mane (Cyanea capillata).
- Portuguese man-of-war (Physalia physalis in the Atlantic and Physalia utriculus in the Pacific).
- Sea nettle (Chrysaora quinquecirrha), one of the most common jellyfish found along the Atlantic and Gulf coasts.
- Box jellyfish (Cubozoa) all have a box-like body or "bell" with tentacles extending from each corner. There are over 40 species of box jellies. These range from nearly invisible thimble-sized jellyfish to basketball-sized chirodropids found near the coasts of northern Australia, Thailand, and the Philippines (Chironex fleckeri, Chiropsalmus quadrigatus). Sometimes called "sea wasps," box jellyfish are highly dangerous, and more than 8 species have caused deaths.  Box jellyfish are found in the tropics including Hawaii, Saipan, Guam, Puerto Rico, the Caribbean, and Florida, and recently in a rare event in coastal New Jersey.
P There are also other types of stinging jellyfish.
P If you are unfamiliar with an area, be sure to ask local ocean safety staff about the potential for jellyfish stings and other marine hazards. In areas where box jellies may be found, especially at sunset and sunrise, full body coverage with a"stinger suit" hood, gloves, and booties is advised.

T Symptoms
P Symptoms of stings from different types of jellyfish are:
P LION'S MANE
- Breathing difficulty
- Muscle cramps
- Skin burning and blistering (severe)
P PORTUGUESE MAN-OF-WAR
- Abdominal pain
- Changes in pulse
- Chest pain
- Chills
- 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
P SEA NETTLE
- Mild skin rash (with mild stings)
- Muscle cramps and breathing difficulty (from a lot of contact)
P SEA WASP OR BOX JELLYFISH
- Severe burning pain and sting site blistering
- Raised red spot where stung
- Skin tissue death
- Breathing difficulty
- Sweating
- Nausea and vomiting
- Abdominal pain
- Changes in pulse
- Chest pain
- Collapse
- Headache
- Muscle pain and muscle spasms
- Pain in the arms or legs
P For the great majority of bites, stings, or other forms of poisoning, the danger is either drowning after being stung or an allergic reaction to the venom.

T Home Care
P Seek medical help right away. Get medical attention right away if pain increases or there are any signs of breathing difficulty or chest pains.
- As soon as possible, rinse the sting site with large amounts of household vinegar for at least 30 seconds. Vinegar is safe and effective for all types of jellyfish stings. Vinegar rapidly halts the thousands of tiny unfired stinging cells left on the surface of the skin after tentacle contact.
- If vinegar is not available, the sting site can be washed with ocean water.
- Protect the affected area and do NOT rub sand or apply any pressure to the area or scrape the sting site.
- Soak the area in 107°F to 115°F (42°C to 45°C) standard tap hot water, (not scalding) for 20 to 40 minutes.
- After soaking in hot water, apply antihistamine or steroid creams such as cortisone cream. This can help with pain and itching.

T Before Calling Emergency
P Have this information ready:
- Person's age, weight, and condition
- Type of jellyfish, if possible
- Time the person was stung
- Location of the sting

T Poison Control
P 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.
P 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.

T What to Expect at the Emergency Room
P 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, may be used for one specific box jelly species found only in certain areas of the Indo-Pacific (Chironex fleckeri)
- Blood and urine tests
- Breathing support, including oxygen, a tube through the mouth into the throat, and breathing machine
- Chest x-ray
- ECG (electrocardiogram, or heart tracing)
- Fluids through a vein (by IV)
- Medicine to treat symptoms

T Outlook (Prognosis)
P Most jellyfish stings improve within hours, but some stings can lead to skin irritation or rashes that last for weeks. Contact your provider if you continue to have itching at the sting site. Topical anti-inflammatory creams may be helpful.
P Portuguese man-of-war and sea nettle stings are rarely deadly.
P Certain box jellyfish stings can kill a person within minutes. Other box jellyfish stings can lead to death in 4 to 48 hours after a sting due to "Irukandji syndrome." This is a delayed reaction to the sting.
P It is important to carefully monitor box jellyfish sting victims for hours after a sting. Seek medical attention right away for any breathing difficulties, chest or abdominal pains, or profuse sweating.

T References
P Otten EJ. Venomous animal injuries. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 55.
P Sladden C, Seymour J, Sladden M. Jellyfish stings. In: Lebwohl MG, Heymann WR, Berth-Jones J, Coulson IH, eds. Treatment of Skin Disease: Comprehensive Strategies. 4th ed. Philadelphia, PA. Elsevier; 2018:chap 116.
P Tibballs J, Yanagihara AA, Turner HC, Winkel K. Immunological and toxicological responses to jellyfish stings. Inflamm Allergy Drug Targets. 2011;10(5):438-446. PMID: 21824077 www.ncbi.nlm.nih.gov/pubmed/21824077.
P Wilcox CL, Yanagihara AA. Heated debates: hot-water immersion or ice packs as first aid for cnidarian envenomations? Toxins (Basel). 2016;8(4):97. PMID: 27043628 www.ncbi.nlm.nih.gov/pubmed/27043628.
P Yanagihara AA, Wilcox C, King R, Hurwitz K, Castelfranco AM. Experimental assays to assess the efficacy of vinegar and other topical first-aid approaches on cubozoan (Alatina alata) tentacle firing and venom toxicity. Toxins (Basel). 2016;8(1):pii: E19. PMID: 26761033 www.ncbi.nlm.nih.gov/pubmed/26761033.
P Yanagihara AA, Wilcox C, Smith J, Surrett GW. Cubozoan envenomations: clinical features, pathophysiology and management. In: Goffredo S, Dubinsky EZ, eds. The Cnidaria, Past, Present and Future: The World of Medusa and Her Sisters. Switzerland. Springer; 2016:637-652.

T Review Date 7/12/2017
P Updated by: Jacob L. Heller, MD, MHA, Emergency Medicine, Emeritus, Virginia Mason Medical Center, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

