If a patient presents in the summer with a blistering rash on their hands, around their mouth or in an elongated drippy pattern down the front of their body, ask what they’ve been drinking.
A rare skin reaction left a man in Florida with second-degree, blistered chemical burns on his hands on May 26, 2015, just days before his wedding, according to a news report in USA Today (June 2, 2015). The culprit was lime juice, which had caused phytophotodermatitis, making the man’s skin hypersensitive to ultraviolet (UV) radiation.
Many plants contain photosensitizing compounds that can lead to phytophotodermatitis, but because some of them – lemons and limes in particular – are used in mixed drinks consumed in hot weather, the condition has also picked up the name margarita dermatitis (N Engl J Med 1993; 328(12): 891), and incidence rises in the summer. The authors of the article note that lime juice contains furocoumarin, a lipid-soluble 8-methoxypsoralen, which permeates into keratinocytes and binds to the cells’ DNA after exposure to long-wavelength ultraviolet A radiation, permanently damaging the cells and resulting in erythema, burning edema, and vesiculation within 24 hours after exposure. Post-inflammatory hyperpigmentation can then follow.
Dermatologist Dr. Douglas Robins of Jacksonville, Florida, told USA Today that he sees about 12 patients a year with the condition, and that it can take years for the skin in the effected area to return to normal. However, Dr. Robins notes that it is not known what makes a given person susceptible. “If you've never had it before that doesn't matter," Dr. Robins said. "It's a combination of lime juice and the sun,” he told the news outlet.
Originally published in The Chronicle of Skin & Allergy (Aug. 2015; 21(5):3).