A healthcare worker suffered severe burns after squeezing "hundreds of limes" to make cocktails for a party.
Courtney Fallon prepared the margaritas and lounged for a a spot of sunbathing in Florida, US.
But when she woke, she said her skin felt like it was "on fire" and her hands were covered in large blisters.
Doctors diagnosed the woman with "margarita burn", medically known as phytophotodermatitis, which is a common skin reaction worsened when the skin has been in contact with UV-sensitive substances - like lime.
It is understood Courtney, from New York, thought she had suffered sunburn and was surprised to hear the diagnosis.
But Clarissa Yang, MD, chief of dermatology at Tufts Medical Center in Boston, told New York Post : "When you get a substance on the skin that’s photo- or UV-sensitive, it creates a phototoxic reaction after sun exposure, the severity of which will be proportionate to how much of the agent touched the skin."
She explained the symptoms can take up to three days to manifest.
It is believed the lime juice may have run down Courtney's arm and, when exposed to UV light, the chemicals created a photochemical reaction to the skin, damaging skin cells and killing them.
"Just wash your hands," Dr Yang continued.
Or she suggested wear gloves when preparing cocktails in the sun this summer.
But the medic warned against picking or peeling the hardened skin as this can cause scars.
Suncream is also very important, she stressed.
