Jellyfish sting: what is the first thing to do

Jellyfish are becoming increasingly common, meaning that accidental contact with them is becoming more and more likely. While usually not emergencies, jellyfish can cause major contact injuries, so it is always good to be prepared.

What are jellyfish?

Jellyfish are coelenterates within the Cnidaria phylum, in the Scyphozoa class. The term ‘scyphozoa’ means ‘cup-shaped’ and is a nod to the shape of jellyfish. Jellyfish have special cells called cnidoblasts that contain a stinging structure called a nematocyst. As soon as the jellyfish is touched, the nematocyst ejects a filament that is coiled around itself and that sticks into the external object or animal.

Why are jellyfish numbers increasing?

There are several hypotheses as to why jellyfish numbers are increasing, but the most likely are due to pollution, warmer waters, and biological cycles.
Pollution is in part due to the numerous fertilizers that end up in the waters near the coasts, creating a favorable habitat for jellyfish reproduction.
Moreover, warmer waters lead to a greater plankton presence, providing jellyfish with an ample food supply.
Finally, some researchers have found that while jellyfish breed in open seas, they will usually move to breed near shorelines in a cycle of every ten to eleven years.

Different types of jellyfish

There are three types of jellyfish that are the most commonly found in the Mediterranean Sea:

The mauve stinger or luminous jellyfish (pelagia noctiluca)

The mauve stinger or luminous jellyfish (pelagia noctiluca) are bioluminescent. They are about 10 cm in diameter, with long, fine tentacles. They are particularly dangerous as they appear in schools of many hundreds.

The fried egg jellyfish (cotylorhiza tuberculata)

The fried egg jellyfish (cotylorhiza tuberculata) are domed, with arms that circle the base of the mouth, to look like an upturned bouquet of flowers.

The barrel jellyfish (rhizostoma pulmo)

The barrel jellyfish (rhizostoma pulmo) is the largest of those found in the Mediterranean, measuring up to 60cm in diameter. They have a milky white dome surrounded by a violet margin.

Jellyfish tentacles

Jellyfish tentacles are lined with special cells called cnidocytes that can inject venom into prey. They can be used for both defensive and offensive functions: the venom can kill smaller prey that the jellyfish can use for food; or it can ward off larger animals that are potentially dangerous to the jellyfish.

Jellyfish venom

Jellyfish venom is usually made up of a mixture of three proteins: one with a paralyzing effect, one with an inflammatory effect, and one that is neurotoxic.
Although the venom of some larger jellyfish can cause anaphylactic shock and death in humans, contact with regular jellyfish venom usually only causes a local, inflammatory reaction.

Skin reactions after jellyfish contact

Immediately after coming into contact with jellyfish tentacles, the skin will become extremely reddened, welts form and there will be burning pain. This burning sensation usually lasts for about thirty minutes, before the area becomes very itchy.
The degree of burning pain will differ depending on the size of the area stung and can become unbearable if more than 50% of the body surface is affected.
In some individuals, the jellyfish sting can turn into a semi-permanent reaction (usually pigmentation or inflamed, itchy skin) that may last for months or years.

La sensazione di bruciore dura 30 minuti circa, poi si trasforma in sensazione di intenso prurito.
Il grado di dolore bruciore è differente a seconda delle aree di pelle colpite e può diventare insopportabile se viene colpita più del 50% della superficie corporea.
In alcuni soggetti la reazione da puntura di medusa si trasforma in una reazione permanente che dura mesi o anni in forma di pigmentazione o di cute infiammata e pruriginosa.

What are the outcomes?

The area of skin affected by a jellyfish sting will remain sensitive to sunlight and tends to darken rapidly. To prevent the skin from scarring, keep the affected area covered until the inflammatory stage has passed, which will usually occur within a couple of weeks.

What’s the first thing to do if you get stung by a jellyfish?

Firstly, do not panic or scream, and try to breathe normally. If nearby the shore, get out of the water and reach land as soon as possible. If offshore, attract the attention of the nearest boat and board. Once out of the water, check that there are no jellyfish parts left attached to the skin. If so, they must be removed. If no means of dressing is available, the only thing that will help is to run seawater over the sting, which will dilute any venom that has not yet penetrated the skin. Avoid scratching, rubbing sand or resorting to impromptu dressings with ammonia, vinegar, alcohol or other DIY remedies on the area, as these will only make the situation worse.

What to do if stung by a jellyfish

Proceed with the application of Astringent Gel containing aluminum chloride. With immediate antipruritic action, Astringent Gel also helps to neutralize any venom that has not yet penetrated the skin.
Inflammation and signs of the skin will quickly die down after application.

What not to do if stung by a jellyfish

The use of cortisone or antihistamine-containing creams are not recommended. This is because they only take effect around thirty minutes after application, which is when the most intense reaction to the jellyfish sting has already occurred.

When to seek further help

If the reaction to the jellyfish sting is widespread across the skin and the individual experiences difficulty breathing, paleness, sweating, and disorientation, call emergency services immediately. They will provide further instructions on what to do while awaiting the arrival of paramedics.

Conclusion

Jellyfish stings are a more common occurrence than one might think, but are usually not emergencies. The important thing is not to panic, and to follow DermaClub’s advice.