Ally Barons: I just have always grown up around water, and I love to swim.

Vivien Williams: But last year, during spring break, lifeguard Ally Barons developed a strange, long, red mark on her leg after a dip in the ocean.

Ally Barons: But then it started to get really red and blistered.

Vivien Williams: She thought maybe it was a jellyfish sting. Mayo Clinic Dr. Dawn Davis told Ally yes, it was a sting, but from a plant and the sun, not a jellyfish.

Ally Barons: So I was kind of disappointed because jellyfish sounds cooler.

Dawn Marie R. Davis, M.D.: There are certain plants and fruits in nature, such as dill, buttercup, bergamot, musk ambrette, parsley, parsnip, and citrus fruits, especially lime, that when these chemicals that they contain hit your skin and then it's exposed to ultraviolet light, a chemical reaction occurs. And you can either develop a dermatitis, which is called phytophotodermatitis, plant-light induced eczema, or you can develop a phototoxic dermatitis, meaning plant sunburn dermatitis.

Vivien Williams: Typical scenarios would be when you brush up against certain plants on a hike or when you squeeze a lime into a drink, maybe you get some juice on your hands, you touch your arm. And when the sun hits that spot, the dermatitis appears in the form of hand prints or drips.

Dawn Marie R. Davis, M.D.: A lot of people think that it's poison ivy with the lines and the streaks. But it's, indeed, not. It's a phytophotodermatitis.

Vivien Williams: Treatment includes topical ointment and staying out of the sun.

Ally Barons: It's right here on my leg.

Vivien Williams: Ally says her reaction was a bit painful, but over time it's fading away. For Medical Edge, I'm Vivien Williams.

Sept. 20, 2022