They may look innocuous, but jellyfish can pack a serious sting. And with some species benefitting from oceans warming due to climate change, the number of swimmers getting a nasty surprise in the water is likely to rise. There has long been a debate whether it's best to treat jellyfish stings with heat or cold, and now a team from the University of Hawaiʻi at Mānoa claims to have reached a definitive answer.
For their study, the researchers trawled through the databases of major scientific journal article databases to find every study examining the effects of using temperature-based treatments for jellyfish stings to date. After combing through more than 2,000 related articles, they discovered that the vast majority of evidence came out on the side of hot-water immersion.
"People think ice will help because jelly stings burn and ice is cold," said Christie Wilcox, lead author of the paper. "And if you Google it, many sites – even those considered reputable – will tell you to put ice on a sting to dull the pain. But research to date has shown that all marine venoms are highly heat sensitive, thus hot water or hot packs should be more effective than cold packs or ice."
Before you start thinking this may lend some credence to the old myth that urinating on a jellyfish sting is a good idea, the water needs to be warmer than the 36° C (96° F) that urine leaves the body at to have a beneficial effect – specifically about 45° C (113° F). The researchers say this is in keeping with research that has shown marine venom components are inactivated at temperatures between 40 and 50°C (104 and 122° F).
Not only did the researchers find that hot-water immersion was the key to reducing pain from jellyfish stings, but that it was associated with improved clinical outcomes. Additionally, no studies reported cases of hot-water immersion leading to worse symptoms or poorer clinical outcomes.
"I was shocked that the science was so clear, given that there is so much debate over the use of hot water," says Wilcox. "It's simple, really: if you're stung, use hot water or hot packs rather than ice or cold packs."
The researchers hope their findings will be taken on board by first responders and public health decision makers who may have been swayed by "authoritative web articles" giving bad advice on the best way to treat jellyfish stings.
Their study appears in the journal Toxins.
Source: University of Hawai'i
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