Researchers Find Best Treatment for Man o’ War Stings

A freshly caught Physalia physalis. Credit: Rachel Skubel.

Trusted first aid sources have recommended that Portuguese man o’ war jellyfish stings be treated differently from others. But scientists at the University of Hawai‘i at Mānoa (UHM) have researched current literature and found little evidence to support unique treatment for these stings.

Members of the Pacific Cnidaria Research Laboratory (PCRL) at UHM, Christie Wilcox, lead author of the paper and postdoctoral fellow, and Angel Yanagihara, senior author, head of the PCRL and assistant research professor at the UHM Pacific Biosciences Research Center and John A. Burns School of Medicine, teamed up with researchers in Ireland to find out what first aid methods are most effective for man o’ war stings.

Their results, published in the journal Toxins, suggest that man o’ war stings are no different than other jellyfish stings. Accordingly, the best first aid action for these stings is to rinse them with vinegar, removing any stingers or pieces of tentacles on the skin, followed by immersion in hot water or application of a hot pack for 45 minutes. In contrast, research by Yanagihara and Wilcox found that common first aid tactics of rinsing with seawater and applying ice packs actually made stings much worse.

Physalia are commonly stranded on shorelines in Hawai‘i when onshore winds push thousands of the small, painful jellies onto beaches. They are easily recognized by their bright blue tentacles and colorful inflated floating sails.

Treatment methods for man o’ war stings from the Atlantic species of Physalia are the same. In a parallel study, Yanagihara teamed up with Tom Doyle, a jellyfish scientist and lecturer with the National University of Ireland (NUI) Galway. Doyle and his team researched the Atlantic man o’ war and found that first aid using vinegar and hot water immersion or a hot pack are the best method of treatment.