What to do when you've been stung by a jellyfish

It’s not uncommon to see a jellyfish at the beach or in the sea. Some won’t harm you, but others can be very dangerous.   

Here’s what you need to know about tropical jellyfish stings. 

Hamish says the box jellyfish species, found in tropical Australia, is the one to be most concerned about. It’s box-shaped with venomous tentacles hanging off it.  

“The major box jellyfish can be fatal,” Hamish says. The venom in its tentacles can potentially kill a person within five minutes. And children, because of their smaller size, are at greater risk if stung. 

But there’s another, smaller, box jellyfish species called the Irukandji (only about 2cm in diameter) that can also be extremely venomous. It’s typically found in waters from Bundaberg in Queensland right around the coastline to Geraldton in Western Australia. 

“The problem with Irukandji is that the initial sting is often not particularly painful. But then 30 minutes later pain and cardiac symptoms can develop,” Hamish notes. 

The bluebottle is another type of marine creature that stings and is found throughout most of Australia. However, while a bluebottle sting is painful and can leave whip-like lines on the skin, it is not fatal. Pain usually stops in a couple of hours, although you may have joint aches and a rash on the skin after – learn what to do by visiting nib’s bluebottle article.

You might not know what type of jellyfish has stung you, but if you’re in tropical waters it’s best to treat the sting as if it was a major box jellyfish sting. 

The first symptoms of a major box jellyfish sting will be mild to severe pain and a goosebump-like skin reaction. But these symptoms can quickly worsen to vomiting, headache, difficulty breathing and an irregular heartrate. In extreme cases, venom can cause heart failure, swelling of the brain and death. 

Irukandji sting symptoms can include a severe backache or headache, shooting muscular pain, vomiting, nausea, anxiety and breathing difficulties.  

For any sting in tropical waters, you should: 

1. Remove the person with the sting from water.  

2. Call 000 or seek the help of a lifeguard, if available. 

3. If they are unconscious, start CPR. 

4. Apply vinegar (if you have it) liberally to the jellyfish. This can stop the stingers from firing. 

5. If there is no vinegar, remove the tentacles by flicking them off with a stick-like object or your fingers (wear gloves if available). Rinse the sting site with seawater. 

6. If you’re with someone who has been stung, monitor their pulse and breathing and start CPR if needed. 

7. If an ambulance isn’t on its way, head straight to hospital. 

DO seek treatment when you are stung in tropical water. This is because of the chance you’ve been sting by a box jellyfish, says Hamish. 

DON’T pour fresh water into the sting because this can cause more venom to be released. And don’t rub the sting site. 

Stay out of the water during “stinger season” – from about November to May – or where there are specific warnings. Don’t touch a jellyfish.  

Where there’s a risk of jellyfish, wear a wetsuit or stinger suit that covers as much as your body as possible. Swim on patrolled beaches where lifeguards can help. 

Please note: The tips throughout this article serve as broad information and should not replace any advice you have been given by your medical practitioner.