Jellyfish stings hurt, and some of them can even be deadly. But the sting of the Portuguese man o’war—which is technically a siphonophore and not a jellyfish—is particularly painful.
The creatures float around using an air bladder and are often pushed en masse onto beaches by wind and water currents where they sting unsuspecting beachgoers. For years, first aid manuals have suggested treating man o’ war stings differently than those of jellyfish. But as George Dvorsky reports for Gizmodo, a new study suggests that’s not necessary. In fact, most of the common treatments recommended for jellyfish and man o’ war stings actually do more harm than good. The researchers published their results last week in the journal Toxins.
According to a press release, Angel Yanagihara, senior author of the study and head of the Pacific Cnidaria Research Laboratory at the University of Hawaii, Manoa, began the project with box jellyfish, considered one of the deadliest creatures in the world. She designed a set of models that mimic human tissue to test the best ways to treat their stings.
Those tests revealed that some common recommendations, like applying urine to the sting or scraping off the tentacles, just made things worse. “Without solid science to back up medical practices, we have ended up with conflicting official recommendations around the world, leading to confusion and, in many cases, practices that actually worsen stings or even cost lives,” Yanagihara says in the press release.
So the researcher decided to run similar tests on the man o’ war, collaborating with jellyfish specialist Tom Doyle at the National University of Ireland in Galway. The duo performed the same experiments on man o’ wars from around Ireland and Hawaii. As Dvorsky reports, the researchers found many potential treatments—including dousing the sting with urine, alcohol, soda, lemon juice and dish soap—all caused the cnidae, which are the microscopic capsules tipped with stingers that do the damage, to discharge more toxins. None of these treatments stopped them from stinging. One common treatment, rinsing the sting with seawater, was particularly bad and just spread the cnidae over a wider area.
So what does work? It turns out that rinsing the sting with vinegar then immersing the area in water 113 degrees Fahrenheit or hotter for 45 minutes will deactivate and rinse away the cnidae as well as deactivate the venom already injected. A product developed by the U.S. military for combat divers called Sting No More also works.
Current guidelines recommend vinegar for jellyfish stings but discourage the use for man o’ war. “Given that most recommendations expressly forbid the use of vinegar and recommend seawater rinses, these findings completely upend current protocols,” Yanagihara says in the press release.
For Doyle, the result means eating some crow. A decade ago, he helped put together the protocols for treating stings in Ireland, which recommend rinsing the sting in seawater and using an ice pack, more or less the opposite of what the study's results.
The team will now set their sights on the Scyphozoa, or the true jellyfish, to figure out the best way to treat their stings. This means that there’s still a chance this disturbing but classic scene from the TV show Friends might turn out to be best practice.