Jellyfish stings What to do if a jellyfish bites you?

Before starting a fantastic day at the beach with the family, we must pay special attention to information from authorities or lifeguards about the state of the beach, which can warn us of the presence of jellyfish in its waters.

It is possible to find specific flags to signal the presence of jellyfish, in addition to the red one (prohibits bathing) or the yellow one (bathroom advised against, great caution).

Why does jellyfish sting hurt?

  • In the jellyfish tentacles are the nematocysts, microscopic stingers with a toxic substance that fulfills the functions of defense and capture of prey.
  • When we brush the tentacles, those stingers come off with toxins that cause itchy, painful, burning, swelling, redness and possible slight bleeding in our skin. In most cases, dermatological lesions disappear within a few days, although discomfort may last longer.
  • These toxins remain encapsulated in the tentacles even when the jellyfish die, so we should always avoid touching them.

The reaction will occur more easily in areas of thinner and more delicate skin (lips, eyelids) and especially in young children

What to do about a jellyfish sting?

  1. Get out of the water as soon as possible

  2. If there are traces of tentacles on your skin, carefully remove them with tweezers or another rigid object (eg card type card). Do not manipulate directly with your hands

  3. Clean the affected area with salt water or physiological serum. Never with fresh water or rubbing because it can favor the release of more toxins

  4. Do not apply ammonia, vinegar or urine

  5. If symptoms are not relieved, go to the aid station or a nearby health center. Remember that only healthcare professionals can give you medication

  6. If you have witnessed, accompany and monitor the person who has suffered the sting. Make sure you are well and alert if you see signs of worsening (vomiting, malaise, muscle cramps, dizziness, loss of consciousness)

  7. Elderly, allergic or young children may require special attention.


Preevid Question Bank. Management of the bite by Portuguese caravel. Murciasalud, 2018. Available in

Types of jellyfish in the Mediterranean and the Atlantic

  • Cotylorhiza tuberculata (aguacuajada, jellyfish fried egg or curled acalefo):
    • Common throughout the Mediterranean in open water and coast during summer and autumn
    • Short tentacles, 20-35 cm umbrella
    • Low hazard, bite with very mild symptoms.

Jellyfish sting Cotylorhiza tuberculata

  • Pelagia noctiluca (luminescent jellyfish):
    • Common in Mediterranean and Atlantic in open water during the summer. The currents drag them to coast
    • Long tentacles, 20 cm umbrella
    • High danger, frequent irritation and stinging.

Jellyfish sting Pelagia Noctiluca

  • Rhizostoma pulmo (aguamala, aguaviva or acalefo azul):
    • Abundant in the Mediterranean and Atlantic from late spring to autumn
    • Robust and short tentacles, 90-100 cm umbrella
    • Medium hazardfrequent irritation

Jellyfish sting Rhizostoma Pulmo

  • Chrysaora hysoscella (compass jellyfish or radiated acalefo):
    • Common in Mediterranean and Atlantic in open water during the summer. The currents drag them to coast
    • Long and thin tentacles up to 5 m, umbrella of 30 cm
    • High danger; frequent irritation, burning and the appearance of warts that take time to disappear.

Jellyfish sting Chrysaora Hysoscella

  • Physalia physalis (fisalia, Portuguese caravel): The dreaded Portuguese skull is not a jellyfish, although its sting can be deadly in children.
    • Common in temperate and surface waters of the Atlantic, occasionally in the Mediterranean
    • Thin and long tentacles of up to 20 m, umbrella of 30 cm
    • Very high danger; sting causes very intense pain and serious neurological and cardiological consequences

Portuguese Calavera jellyfish sting

  • Aequorea forskalea (jellyfish aequorea):
    • Common in Atlantic and increasingly frequent appearance in Mediterranean
    • Thin filaments, umbrella 30 cm
    • Zero danger, does not produce sting

Aequorea Forskalea jellyfish sting

Source consulted:

To keep in mind how you should act in case of suffering a jellyfish sting, we have created a very visual infographic to know what to do if you are present during an episode of jellyfish sting, Can you help us keep raising more people?


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