There are over 2,000 varieties of jellyfish in the world, about 70 of which are harmful to humans. They are found in every ocean on the planet, and some even live in freshwater lakes.
With that many jellies bobbing around in the water, chances are good you’ll encounter one sooner or later, and getting too close could result in a painful sting. Fortunately, treating most jellyfish stings is fairly simple if you have the right tools.
On the other hand, how do jellyfish sting and how bad can they be?
How Do Jellyfish Sting?
As many of us already know, it’s the jellyfish tentacles that actually do the stinging and not its round (or boxed) heads. Along these tentacles are cnidocytes, which are cells that contain harpoon-like and venom-filled secretory organelles called nematocysts. When these stinging cells are triggered by touch, they shoot out to release venom into the skin.
Unfortunately for oblivious swimmers, the venom penetrates the skin in no time. What causes the pain and discomfort is a type of protein called a porin, which is found in the venom of all cnidarians—a group of sea creatures that include all species of jellyfish, corals, and anemones.
Jellyfish Sting Reactions
While all types of jellyfish do sting, not all of them are harmful. Some of them may cause uncomfortable stings, at most, while a few of the most poisonous species of jellyfish (like the chironex fleckeri box jelly or sea wasps) should be avoided at all costs.
A common telltale sign of a jellyfish sting is red, brown, or purplish tentacle track marks along the skin. To get an idea, you can check out what different jellyfish stings look like. These could be accompanied by any of the following:
- Itching and burning
- shooting pain
- skin necrosis
- severe allergic reactions
- shortness of breath
- muscle spasms
Species of box jellyfish, which primarily live in the waters off Northern Australia and throughout the Indo-Pacific, are also known to cause cardiovascular failure, paralysis, and even death while still in the water.
If you or anybody you know gets stung by a jellyfish, call emergency services if:
- The person is showing signs of a severe allergic reaction
- The sting is from a box jellyfish (cube-shaped head)
- The sting covers more than half an arm or leg
Otherwise, you can move on to the first aid treatments below.
How to Treat a Jellyfish Sting
Once you’re sure that the victim is not in immediate danger, the following steps of jellyfish sting treatment will help improve the situation before it gets worse.
Get out of the water
As soon as you or a fellow swimmer realizes that you’ve been stung by a jellyfish, focus your efforts on getting out of the water. There’s no assurance that simply swimming away could help the person avoid the stinging jellyfish—after all, there could be more of them—so the best way is to get back on board or on shore.
Rinse the area
Don’t waste time. Start rinsing the area with hot (but not scalding) water while you observe the affected area. If there’s no heated water, use salt water instead of freshwater as the latter can worsen the pain.
Although the use of plain white distilled vinegar (acetic acid) has become controversial in recent years, it remains the standard first aid treatment in deactivating nematocysts that may still be on your skin. If you already have it, go ahead and rinse the area with vinegar. It at least helps prevent it from getting worse and you’ll want to do everything you can—especially if you’ve been stung with box jellyfish venom.
It’s important is that you don’t stop rinsing the area with what you already have until you’re ready for the next step. And whatever happens, don’t rub or pee on it!
Remove any tentacles
Avoid scraping off the tentacles as this could only worsen the pain. Instead, use a pair of tweezers to gently remove any visible pieces of tentacles off the skin. Whoever is taking this step should wear gloves for protection. If you must use your bare hands, rinse them with vinegar and hot water immediately afterward.
Soak affected area in hot water
After removing every piece of tentacle that may have clung to the skin, soak or shower the stung area in the hottest water that the person can stand (around 104-113°F or 40-45°C) for at least 20 minutes. If possible, stay in the water as long as needed and gently pat dry with a towel afterward.
Treat the discomfort
Once the affected area is dry, you can use ice or some heat to help with the discomfort. You can also use a mild hydrocortisone cream or a topical anesthetic like Salonpas or Blue-Emu to ease the pain, itching, and swelling.
Oral painkillers like ibuprofen (Advil, Motrin) and acetaminophen (Tylenol) have also been known to help relieve some pain. For those who prefer an oral antihistamine, you can try diphenhydramine (Benadryl), but watch out for a deadly allergic reaction called anaphylaxis.
The victim may still feel some pain and discomfort hours to a few days after the initial sting. For less severe stings, you can simply continue with your hot or cold compress and over-the-counter pain relievers or antihistamines. Treat open sores by cleaning them three times a day and applying some antibiotic ointment. Cover it with a sterile bandage, if needed.
For more life-threatening reactions, you may have to stay in the hospital for a few days. Box jellyfish stings may be treated with some antivenin (an antivenom) as soon as you get to the emergency room to stabilize the poisoning.
No matter what you do, avoid employing home remedies like baking soda, urine, alcohol, and fresh water. Most of them don’t even work, so don’t try them.
Most jellyfish encounters result in nothing more than some minor irritation and a cool story, but being aware of the marine life that inhabits the area in which you are diving is always a good idea. When heading into unfamiliar waters, talk with local divers or research what kind of jellyfish might be lurking below just to be on the safe side.