Stings from jellyfish tentacles

Treatment tips for jellyfish burns as well as recommendations for bathers

On the 20th of July 2015, an article was published in the Valencian Newspaper, Del Levante, about jellyfish venom suspended in the waters, which caused at least ten people to seek medical help at the lifeguard station on the Saler beach. The presence of jellyfish on Spanish beaches is quite common during the summer. The high temperatures, good weather, a calm sea during the day and crystal clear water form ideal conditions for jellyfish, which appear in large banks a few hundred metres from the shore. Although not visible to bathers, the jellyfish produce a toxic liquid, which remains suspended in the seawater. When there is no strong current it can accumulate and cause irritation to the skin. In reality it has never become too serious as the species of jellyfish in our Mediterranean waters are not lethal, but they can cause serious complications to anyone that is allergic or has depressed immunity.

Sex and age of the patient

Male 29 years old from Ourense.


He visited a surgery at a Madrid Clinic one and a half weeks after having been stung by jellyfish tentacles on a beach in Ibiza, to have the skin lesions checked and for treatment for the residual itching.

He confirmed that he hadn’t seen the jellyfish and hadn’t felt the sting at the time; he mentioned that he had been drinking. He confirmed that he had been close to the shore but had not been diving or swimming in deep water. He mentioned that he received an antibiotic treatment for the skin lesions and an antibacterial ointment and Vaseline dressing from a medical centre on the island.

Physical examination

Afebrile. In perfect general condition at the time of the examination, no changes the cardiopulmonary, and gastrointestinal levels or difficulty urinating.

On the skin on the left arm, mainly around the left shoulder there is extensive burning by the jellyfish tentacles and residual erythema, peeling and loss of the previously infected tissue with deep welts, and but with no evidence of further infection.

Treatment consisted of a healing ointment and anti-inflammatory and something to ease the itching.

Information and advice for prevention and treatment

Jellyfish, are the most primitive of marine animals, and are a strain of Cnidarian (from the Greek knide=nettle) with a gelatinous body in the shape of a bell from which hangs a tubular bar with a mouth at the bottom, often elongated by tentacles loaded with stinging cells called Cnidocytes. They appeared over 500 million years ago during the Palaeozoic period.

The body of the jellyfish is 95% water and the tentacles are formed from stinging cells, nematocysts or cnidocytes, which are used to capture prey and to defend themselves. These cells contain a capsule with a toxic/poisonous filament. On contact with their prey, the filaments react automatically and fire a type of dart, which enters the skin, injecting a poison. The cells explode with either a thermal (temperature) or osmotic (saline) shock. The difference between the sea temperature and the body of the animal, which is normally higher, causes the cells to burst.

The toxicity of a jellyfish sting varies according to the species. A sting from a Portuguese Man of War (Physalia physalis) or from a sea turtle (Chrysaora quiquecirrah) can be fatal, while a sting from a sea wasp (Chiropsalmus quadrigatus) can cause death within minutes. The majority of jellyfish encountered by bathers on the beaches of Europe cause a painful reaction and a burning feeling, which doesn’t last long. However, we would advise bather to leave the water as son as they can in case they should suffer anaphylactic shock and accidentally drown.

It is important to be aware that the jellyfish tentacles that we sometimes find on the beach, maintain this reflex and can still cause a burn days after the fish has died.


The sting from a jellyfish causes an intense stabbing pain very similar to a bee sting or a burn. The early symptoms are an immediate pain in the affected area, redness, swelling, red blotches and small blisters that can form pustules and peeling. Sometimes it can cause symptoms such as nausea, vomiting and spasms. Anaphylactic shock and death really can happen on the beaches that surround us.

Advice for the treatment of lesions

  • Do not scratch or rub the affected area even with towel or with sand.
  • Wash the area with seawater never with fresh water.
  • Remove any remains or bits with tweezers, or, if you use your hands make sure you are wearing gloves.
  • Apply something cold for about 15 minutes but do not rub. If you use ice, avoid direct contact with the skin.
  • You can use a plastic bag (or glove) filled with ice.
  • Do not apply ammonia, vinegar or urine.
  • If you notice, apart from topical pain such as muscle cramps, nausea, vomiting, sickness, headaches or generally feeling unwell, get to the nearest hospital and if you are able, inform them of the type of jellyfish that stung you.
  • Normally after having been stung it will cause an open wound, which can get infected. It is therefore necessary to protect the wound until it heals, ointments, corticoids and/or antihistamines can help, but before using them seek medical advice.

Recommendations to bathers

  • Jellyfish appear seasonally. In Spain they are more abundant between the beginning of spring and the end of summer. They majority of species spend the rest of the year as a polyp on the seabed or as resistant eggs in the plankton. The presence of large banks of jellyfish that reach our shores during summer is not uncommon in the Mediterranean or other oceans throughout the world. However the amount of them, as well as their appearance on our beaches is determined by weather conditions: rains, winds, currents, etc.
  • It is highly recommended that you use a sun cream; apart from offering protection from the sun it can form a barrier to protect the skin, in this instance from jellyfish tentacles.
  • Don’t underestimate the situation. If you notice a proliferation of jellyfish do not enter the water, even close to the shore, as there may be fragments of their tentacles, which can sting just the same.
  • If in doubt, as the lifeguard for advice.
  • Do not touch dead jellyfish or bits of them; their sting can remain active for up to 24 hours even in dry conditions.
  • If you see jellyfish but no warning has been given, let the lifeguards or beach patrol know immediately.
  • When there are jellyfish the point at which the waves break is the most dangerous, as that’s is where they or fragments of them will accumulate.
  • For anyone about to spend a long time in the water we recommend that they use protective clothing (glasses, wetsuits, lycra ….).

The key: Care once bitten or stung

The wound must be cleaned with seawater, without rubbing or touching it. The remains of the tentacles must be removed using a cloth and then apply something cold to the area.