What happens when you mix margaritas and head outside on a sunny day? You could develop a nasty, itchy rash that may require a visit to the emergency room. The condition, photocontact dermatitis, is nicknamed “margarita rash,” says NBC News, since limes, an integral ingredient in this tasty beverage, are a major culprit.

“It’s surprisingly common in areas that get a lot of sun and have lots of margaritas,” Dr. Kenneth Beer, a board-certified dermatologist from West Palm Beach and leading skincare expert, tells Newsmax. “One of the ingredients in limes, especially Persian limes, can react with light to give an annoying rash. Typically, it occurs on the back of the hands and topical steroids usually do the trick to make it better.”

Experts say the rashes are triggered by furocoumarins, a class of organic chemical compounds found naturally in certain plants like citrus fruits, such as limes, lemons, and grapefruits, celery, parsley, figs and carrots.

Furocoumarins are known for their ability to interact with ultraviolet (UV) light. When exposed to sunlight, they can absorb UV radiation, and this reaction may lead to chemical changes.

The rash may appear hours to days after an exposure and in some cases may linger, says Dr. Brandon Adler, clinical associate professor of dermatology at Keck School of Medicine at the University of Southern California. Adler adds that sometimes the rash goes away quickly but in other cases it may linger and become chronic.

To prevent photocontact dermatitis:

• Wash your hands thoroughly after handling citrus fruits or celery. If you make margaritas or other drinks or dishes that call for citrus fruits, wash your hands and arms with soap and water to get all the juice off.

• Wear sunscreen or protective clothing to reduce UV exposure.

• Avoid squeezing citrus fruits right before spending time in the sun.

To treat a rash or burn, apply a cool compress or a mild topical steroid such as 1% hydrocortisone. Taking an anti-inflammatory drug like ibuprofen may also help, says NBC News.  

However, Adler says that if you notice a rash or blistering on your body after being in the sun, it’s important to see a board-certified dermatologist, who can determine whether you have a sun-related disorder. “No two patients are the same. A board-certified dermatologist can determine what is causing your skin sensitivity and provide a treatment option that works best for your condition,” says Adler.