Jellyfish stings: heat better than cold

Researchers find overwhelming evidence that applying hot packs or immersing in hot water is much better for treating jellyfish stings than cold water which was previously widely recommended.

Jellyfish stings are responsible for more deaths than shark attacks each year. Even “mild” stings can hurt for hours to days and leave lasting scars. According to some estimates, more than 150 million people are stung by jellyfish each year.

The scientists, Christie Wilcox and Angel Yanagihara from the University of Hawaii at Manoa, conducted a systematic review to compare the use of cold or heat in jellyfish sting treatment using a common ranking system for clinical evidence. The pair combed through more than 2,000 related articles from searches of major scientific journal article databases to find every study to date that examined the effects of using temperature-based treatments for jellyfish stings. The overwhelming evidence supported immersing in hot water, finding that venom components are inactivated at temperatures between 40 and 50 degrees Celsius.

“I was shocked that the science was so clear, given that there is so much debate over the use of hot water,” said Wilcox. Hot-water immersion is already the standard of care for other severe marine stings including those from the potentially life-threatening stonefish. “It’s simple, really: If you’re stung, use hot water or hot packs rather than ice or cold packs.”

The scientists conclude that immersing a stung limb in 45 °C water for 20 minutes has no ill effects, is a safe and effective method of reducing pain and improves the outcome of the sting.