Generality
The jellyfish sting is an inflammatory skin reaction resulting from accidental contact with the tentacles of this marine organism.
For humans, this event can be quite annoying: the jellyfish tentacles release stinging substances to the skin, which cause an urticarial-type irritation (pain, redness, itching and swelling).
At our latitudes, the jellyfish sting is usually harmless and the resulting symptomatology can be attenuated with some practical measures. Less often, severe complications can arise, such as allergic reactions or anaphylactic shock, which can compromise the vital functions of the affected person in a short time. In these cases, the timeliness of intervention is fundamental.
What's this
Medusa sting: what is it?
Jellyfish sting is an inconvenience that can be encountered when swimming or diving in the sea. At our latitudes, fortunately, accidental contact with these animals is capable of causing minor problems: jellyfish in the Mediterranean Sea are generally less dangerous than those of tropical seas and Australian coasts.
For humans, jellyfish sting is painful due to the stinging ends of the tentacles .
Medusa: short identikit
- The jellyfish is a marine animal belonging to the phylum of the Cnidarians (or Celenterati).
- The body of the jellyfish is mainly composed of water (around 98%).
- Its generic form is that of an inverted polyp: the upper part (esombrella) is convex, while the lower region (subombrella) is concave. From the margin of the latter the stinging tentacles depart for the purpose of defense and predation.
- The tentacles of the jellyfish can be several meters long.
Causes
Why does jellyfish sting?
In the Mediterranean Sea, jellyfish are present in abundance. It is not rare, therefore, to incur their puncture: in most cases, this occurrence is entirely causal and occurs when one swims or dives.
Jellyfish are marine animals that move vertically, so they are on the surface and can descend to the bottom. Often, these are carried away by the currents, of which they cannot counteract the motion. At this point, it should be noted that jellyfish do not spontaneously attack humans, nor do they deliberately go to swimmers and fishermen; rather, it is the bathers who get too close to the animal and accidentally bump into it.
It is also necessary to point out that jellyfish able to sting usually have very long tentacles: those with which the so-called Portuguese Caravel ( Physalia physalis ) is equipped can even reach 10-20 meters. In other words, if the jellyfish seems far away at sea, its tentacles are not necessarily close.
How does the Medusa sting occur?
First of all, it should be clarified that the jellyfish does not sting, since it does not have a real sting. More correctly, in fact, it is a stinging animal : when the jellyfish is inadvertently touched, the tentacles rest on the skin of the human victim and release strongly irritating substances that produce a skin reaction, similar to a chemical burn of first or second grade .
In detail, the "poison" that causes the typical manifestations of jellyfish sting consists of a mixture of three proteins with a synergistic effect :
- Hypnotoxin : it is responsible for an anesthetic action, thus paralyzing potential prey;
- Thalassin : after the contact between the tentacles and the skin, it is the component that induces the inflammatory response in humans; in people susceptible from the immune point of view, thalassine can be allergenic;
- Congestina : it produces a paralysis of the circulatory and respiratory system of the victims, resulting deadly.
What triggers a jellyfish sting in humans?
In most cases, jellyfish sting causes pain, erythema, itching and swelling . Responsible for this reaction are the tentacles of the marine animal, in which cnidocysts (also known as nematocysts or nematoid cysts ) are found, ie small cellular organelles that contain the stinging substance. The latter consists, as anticipated, of a mixture of three proteins, with inflammatory and neurotoxic effect. The toxins contained in the cnidocysts serve the jellyfish to defend itself and paralyze a potential prey .
The so-called jellyfish sting occurs, therefore, following the contact with the tentacles: when the marine animal collides with a part of the body, the tentacles lean like a suction cup. The cnidocysts are thus deposited on the victim's skin and their breakage releases the poison. The latter is thermolabile, ie it degrades at high temperatures.
The severity of the jellyfish sting depends on various factors, such as:
- Type of jellyfish;
- Geographical area of the accident;
- Size of the affected area;
- Exposure time to the irritant and permanence in water;
- Age, build and health status of the person affected (children and the elderly are more at risk of incurring more severe reactions).
In susceptible people, jellyfish stings can trigger an anaphylactic shock, compromising vital functions in a short time, up to death.
Which jellyfish are more dangerous?
Not all jellyfish are stinging and not all are the same: some are almost harmless to humans, others can cause serious damage, if not even lead to death .
Some tropical species more easily cause an anaphylactic shock . Furthermore, the severe pain that jellyfish bites can be fatal in individuals with heart problems .
In the Mediterranean Sea, more frequently, little stinging jellyfish are observed, such as, for example, the Sea Lung ( Rhizostoma pulmo ) or the Mediterranean Cassiopeia ( Cotylorhiza tuberculata ). In some periods of the year, close to the Italian coasts, however, it is possible to come across the luminous Medusa ( Pelagia noctiluca ), capable of very painful bites.
The most feared species include the Portuguese Caravel ( Physalia physalis ) and the sea wasp ( Chironex fleckeri, also known as cubomedusa).
Symptoms and Complications
Medusa sting: what do you feel after contact?
At the first contact between skin and jellyfish, a strong burning sensation is felt. Immediately afterwards, the skin surface involved becomes red and small wheals appear (skin bulges), similar to those of urticaria . The pain associated with this irritation begins to fade after about twenty minutes, leaving room for intense itching .
Medusa bite: what symptoms does it involve?
The jellyfish sting causes an inflammatory reaction characterized by:
- Localized redness (erythema);
- Skin findings (pomfi);
- Vesicles and bubbles;
- Ache;
- Burning;
- Tingling and numbness;
- Itch.
If the jellyfish sting involves more than 50% of the body, this symptomatology can be extremely intense and the intensity of the pain can become unbearable. Usually, the burning sensation resolves after about 10-20 minutes, but the itching remains.
It should be remembered that the effect of jellyfish sting depends on individual susceptibility (some people are more prone to develop severe reactions), the species in question, time spent in the water and the geographical area of the accident.
Possible complications
If after the jellyfish sting, the skin reaction becomes very extensive and is associated with difficult breathing, mental confusion, profuse sweating, pallor and disorientation, it is good to go urgently to the emergency room. In fact, jellyfish stings can cause an anaphylactic shock and these manifestations can be a wake-up call.
Warning! Some jellyfish are almost harmless to humans: in any case, avoid touching them. Their stinging liquid can remain on the hands, which can easily transfer it to the mouth, eyes or other delicate parts of the body, where it can still cause an inflammatory reaction.
What to do
If you accidentally come into contact with a jellyfish and have not really managed to avoid its sting, you can neutralize the effects with a few simple steps:
- Move away calmly and get out of the water
If you are touched by a jellyfish while you are swimming offshore, it is good not to do unruly movements, trying to move away (as far as possible, without fussing). If you have failed to avoid the animal and its sting, reach the shore, where, if necessary, you can ask someone for help. If you spot a jellyfish while you are already on the shore, instead, it is good to get out of the water immediately.
- Wash the affected area with sea water
In case of jellyfish sting, repeatedly rinse the affected area with sea water, in order to dilute the toxins released by the tentacles not yet penetrated into the skin. On the other hand, avoid fresh water because it could cause cnidocysts to rupture (stinging structures that jellyfish use to defend themselves) left on the skin and increase the victim's pain.
- Clean the skin of residual filaments
Until the tentacles and any remnants of the jellyfish adhere to the skin, they continue to release poison, so they should be promptly removed.
To remove the parts that have remained attached to the skin surface, you must arm yourself with patience and a rigid plastic card (eg credit card) or a knife (not on the side of the blade).
- Go immediately to the emergency room or call 118
If other disorders occur (diffuse skin reaction, nausea, vomiting, profuse sweating, headache, pallor, dizziness, disorientation and difficulty breathing) it is good to seek timely medical intervention. In some particularly sensitive people, in fact, the sting of a jellyfish can trigger an allergic reaction or, worse, an anaphylactic shock. In these cases, the timeliness of intervention is fundamental.
What NOT to do
After a jellyfish sting, symptoms should be avoided and be careful not to run into some common mistakes:
- Watch out for excessive heat
Do not rub the affected area with your hands, sand or a warm stone. The toxins contained in the poison released by the cnidocysts of the jellyfish are actually thermolabile, ie they are inactivated by heat. To produce this effect, however, a temperature of about 50 ° C should be reached, risking a burn.
- Do not rub or scratch the part
After the jellyfish sting, try to resist the temptation to scratch the affected part. Giving in to this instinctive reaction means breaking up any residual cnidocysts, freeing up further poison. After the jellyfish sting, be careful not to touch your eyes and mouth.
- Apply a product based on aluminum chloride
Grandma's remedies, such as ammonia, urine, lemon, vinegar and alcohol, could further ignite the part affected by the jellyfish sting.
To soothe itching, it is best to use a cream or gel based on aluminum chloride, preferably at a concentration of 5% . This product is available in pharmacies and is used to soothe itching and stop the spread of toxins.
When the effects of the jellyfish sting are localized, it is better not to use creams containing cortisone or antihistamine, since they come into action only after about 30 minutes from the application, that is when the reaction is already naturally exhausted. On the other hand, these active ingredients may be okay orally, in the case of widespread lesions or general ailments, subject to the doctor's advice.
- Attention to sun exposure
In the weeks following the jellyfish sting, the redness gives way to a hyperpigmentation that could be made lasting by ultraviolet rays. Therefore, to avoid the appearance of dark skin spots, the part affected by the jellyfish sting should be covered until it is completely healed; alternatively, it is possible to apply a total filter protection (SPF 50+).
Prevention
Is there a way to avoid the jellyfish sting?
- In general, before diving into the water, it is good to look at the surface of the sea : if you spot a jellyfish, even in the distance, it is good to postpone the bath. Moreover, it is better to pay attention to the signs and warning signs placed on the beach .
- The toxins produced by the different species of jellyfish vary, so often different precautions are needed to control pain, further release of poison and local reactions. In other words, useful strategies against a tropical jellyfish can be contraindicated for one of the Mediterranean. Therefore, those who go to areas at risk due to the presence of potentially lethal jellyfish should be aware of the emergency response strategies .
- As a precautionary measure, complete Lycra suits can be worn or the so-called "anti-medusa creams" that make the skin slippery and limit the stinging action of the tentacles, which fail to adhere as usual, can be worn.
Did you know that…
In Australia, jellyfish make more victims than sharks. In some beaches, to keep this marine animal away, especially the larger species, protective nets have been put into the water.
