Squeezing limes for fresh juice may improve the taste of any summer cocktail, but for bartender Justin Fehntrich, it only left him with severe and blistered hands. On a hot summer day this past June, Fehntrich was bartending at a fundraiser on Fire Island, which required that he prep drinks by cutting up and squeezing 100 limes into pitchers for the guests’ cocktails directly under the sun. When a few days later his hand was red, swollen, and covered in bubbly, yellow, fluid-filled blisters, Fehntrich checked into a burn unit.
There, he found out that he was suffering from phytophotodermatitis, otherwise known as “margarita burn.” It occurs when the juice and oil from limes, which contain chemicals called photosensitizers, are exposed to human skin. These photosensitizers make the skin hypersensitive to sunlight, which Fehntrich got in no short supply while working in the outdoor bar of the fundraiser.