Jellyfish Sting Treatment

Dr. Özgür Deniz Tezcan

The Phylum Cnidaria consists of about 10,000 species of animals. Common jellyfish, anemones, corals, sea pens, cube shaped jellyfish all cnidaria with diverse morphology. Cnidaria is characterized by cells called nematocytes (cnidocyte). These cells secrete a very special organelle called nematocyst (cnidocyst). Cnidocyst, sine qua non of cnidaria is used for defense and prey. Inside the cnidocyst, there is an inverted tubule, venom and a huge osmotic pressure. 150 bars. This pressure is comparable to the pressure of a scuba cylinder. When the cnidocyst is triggered, the inverted tubule coiled inside the cnidocyst is everted and ejected with an enormous acceleration. 5.5g. This acceleration is ten times more than a 9mm bullet shot out of a Beretta gun. The tip of the tubule may be as sharp as 80 nm2, i.e. as the diameter of four DNA strands. Together with the speed and sharp tip, it can produce 7.7 GPa pressure at the point of contact. This pressure is higher than the pressure required to produce artificial diamond from graphite.

General information about first aid

The first aid against cnidaria envenomations consists of preventing further nematocyst discharges, alleviating the local effects and controlling systemic reactions. In case of contact with jellyfish generally the tentacles stay attached to the skin and a significant amount of nematocysts are not activated. The nematocysts are sensitive to osmotic changes (like fresh water application) or tactile stimuli (like rubbing). Therefore, it is important to avoid further nematocyst discharge and to remove all the unfired nematocysts as soon as possible.

The safest way to get rid of the unfired nematocysts is to rinse away the sting area by sea water. Remaining tentacles could also be removed by scrubbing the skin by a credit card or dull edge of a knife or detaching by tweezers. Pressure (rubbing, scratching, itching etc.) or rinsing by fresh water, alcohol, methylated spirits should be avoided.

Some chemicals have been shown to stabilize unfired nematocysts so they cannot inject venom. Among them, 5% acetic acid (vinegar) can effectively neutralize the nematocysts of Chironex fleckeri. So, in the first aid of Box jellyfish (class Cubozoa) stings, vinegar application, has taken place as a part of the standard treatment.

But there are conflicting reports about the effectiveness of vinegar for other Cnidarian stings. It has been shown that vinegar trigger the nematocysts of Physalia sp., Pelagia noctiluca, Lytocarpus philippinus and Cyanea capillata. So, most sources recommend vinegar application only to stings from the box jellyfish. One of the more recent promising chemical to stabilize unfired nematocysts could be %1 lidocaine.

Most jellyfish envenomations are mild. They cause slight discomfort or a painful, itchy rash. Although rare, some systemic reactions may be seen like hypotension, hypertension, shock, anaphylaxis, blurred vision, acute renal failure, fulminant hepatitis, autonomous nervous system disturbances, Guillain Barre syndrome, stroke, peripheric neuropathy, etc. The patient should be followed for a probable systemic reaction. The most effective and safe first aid to control the pain is hot sea water immersion. Hot water (43–45°C) immersion of the affected area for 20-40 minutes will ease the pain in most cases. If no thermometer is available, hot water immersion can be applied as hot as can be tolerated.

Myatt, Frederick. 1981. An Illustrated Guide to Pistols and Revolvers. London, United Kingdom: Salamander House.

Birsa L.M. et al. Evaluation of the effects of various chemicals on discharge of and pain caused by jellyfish nematocysts. Comparative Biochemistry and Physiology, Part C 151 (2010) 426–430.

Ward NT et al. 2012. Evidence-based treatment of jellyfish stings in north America and Hawaii. Ann Emerg Med. 2012 Oct;60(4):399-414.

Ozbek S. 2011. The cnidarian nematocyst: a miniature extracellular matrix within a secretory vesicle. Protoplasma. 2011 Oct;248(4):635-40.

Morabito R et al. Nematocyst discharge in Pelagia noctiluca (Cnidaria, Scyphozoa) oral arms can be affected by lidocaine, ethanol, ammonia and acetic acid. Toxicon. 2014 Jun;83:52-8.

Tibbals J 2006. Australian venomous jellyfish, envenomation syndromes, toxins and therapy. Toxicon. 2006 Dec 1;48(7):830-59

Ozbek S et al. 2009. Cnidocyst structure and the biomechanics of discharge. Toxicon. 2009 Dec 15;54(8):1038-45.

Rhizostoma pulmo

1970 ve 1980 lerden sonra gittikçe artan sıklıkta görülmeye başlamıştır. Zehri insanlar üzerinde çok etkili değildir. Deride kızarıklık, kabarma, su toplaması ve yanma şeklinde ağrıya neden olabilir. Özellikle dudaklar gibi ince cilt alanları etkileneir. Hapşırma, burun akıntısı ve ürtikere neden olabilir. R. pulmo teması sonrasında endişeli duygu durum değişikliği bildirilmiştir.


References: Mediterranean Jellyfish Venoms: A Review on Scyphomedusae. Mariottini GL, Pane L. Mar Drugs. 2010; 8(4): 1122–1152.

Venomous and Poisonous Marine Animals: A Medical and Biological Handbook John A. Williamson, Joseph W. Burnett, Peter J. Fenner, Jacqueline F. Rifkin


Phyllorhiza punctata

It may cause slight burning sensation and complaints like itching and tingling. It has only a mild venom and not considered a threat to humans.

Reference: Mediterranean Jellyfish Venoms: A Review on Scyphomedusae. Mariottini GL, Pane L. Mar Drugs. 2010; 8(4): 1122–1152.

Cassiopea andromeda

It is also called "Upside-down jellyfish" because it usually lies mouth upward on the sea bottom. This interesting behavior is caused by the symbiotic relationship with photosynthetic dinoflagellate algae. Jellyfish protects algae by its nematocyst from fish, in turn, algae provides food produced by photosynthesis. Its sting may result in pain, rash and swelling on contact area. Vomiting and muscle pains may occur depending on individuals' sensitivity to the toxin of the nematocysts.

Reference: Mediterranean Jellyfish Venoms: A Review on Scyphomedusae. Mariottini GL, Pane L. Mar Drugs. 2010; 8(4): 1122–1152.

Pelagia noctiluca

Pelagia noctiluca is considered as the most venomous Mediterranean jellyfish. The tentacles, oral arms, exumbrella, and gastric pouches are covered in nematocysts. So all the body parts can string. It is a severe stinging jellyfish causing local symptoms, such as erythema, edema and vesicles as well as persisting pain in the stung skin. Pain completely disappears in 1-2 weeks. Hyper pigmentation may occur on skin. Systemic symptoms are bronchospasm, pruritus, dyspnoea, numbness, nausea, vomiting, low blood pressure, diarrhea, and shock.

References: Jellyfish Stings and Their Management: A Review. Cegolon L et al. Mar Drugs. Feb 2013; 11(2): 523–550.

Impact of Stinging Jellyfish Proliferations along South Italian Coasts: Human Health Hazards, Treatment and Social Costs. De Donno A. et al. Int J Environ Res Public Health. Mar 2014; 11(3): 2488–2503.

Mediterranean Jellyfish Venoms: A Review on Scyphomedusae. Mariottini GL, Pane L. Mar Drugs. 2010; 8(4): 1122–1152.

Chrysaora hysoscella

Chrysaora hysoscella ("compass jellyfish") can be distinguished from other jellyfish by its brown-violet lines on bell surface. Its sting may cause pruritus, erythema, edema and burning. These complaints spontaneously disappear in about a few hours. In some cases, pruritus, erythema, and edema may occur after 48 hours of the contact.

Reference: Mediterranean Jellyfish Venoms: A Review on Scyphomedusae. Mariottini GL, Pane L. Mar Drugs. 2010; 8(4): 1122–1152.

Rhopilema nomadica

This jellyfish, entered the Mediterranean Sea from the Red Sea and increase in the Eastern Mediterranean. It can cause erythema and severe pain in the stung area. In some cases, swelling and rashes like urticaria may occur after 2-7 days of the contact. Skin reactions may be exacerbated by exposure to the sun. It may cause burning and redness on eyes, conjunctivitis, and eyelid edema. Permanent hyper pigmentation, subcutaneous fat atrophy and keloids may occur on the affected area. Systemic symptoms are fever, numbness, and muscle pain.

References: Mediterranean jellyfish (Rhopilema nomadica) sting. Silfen R et al. Burns Volume 29, Issue 8, December 2003, Pages 868–870.

Biologically active polypeptides in the venom of the jellyfish Rhopilema nomadica. Gusmani L et al. Toxicon Volume 35, Issue 5, May 1997, Pages 637–648

Mediterranean Jellyfish Venoms: A Review on Scyphomedusae. Mariottini GL, Pane L. Mar Drugs. 2010; 8(4): 1122–1152.

An alien jellyfish Rhopilema nomadica and its impacts to the Eastern Mediterranean part of Turkey. Öztürk B. İşinibilir M. J. Black Sea/Mediterranean Enviroment Vol.16(2): 149-156 (2010) 

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