It can seem like a harmless garnish in the drink you are sipping by the pool or enjoying on the beach, but some people are finding hours later that that slice of lime has led to a painful, blistering rash.

>> Read more trending news

Certain foods, when combined with a dose of sunlight, can cause a strong reaction on your skin, leading to sunburn or an uncomfortable rash.

In some cases, the condition, called phytophotodermatitis, can be so severe that a person’s skin will blister blisters from slight contact with foods that contain a specific enzyme.

What is phytophotodermatitis and how can you avoid it? Here’s what we know about the skin condition.

What is phytophotodermatitis?

Phytophotodermatitis is a reaction that happens when plants that contain photo-sensitizing agents called psoralens touch your skin. The enzymes cause your skin to be more sensitive to the effects of sunlight, according to the Mayo Clinic.

When your skin is more sensitive to the sun, you are more likely to have sunburns or blistering if you are exposed to the sun for any length of time.

Not only can you develop a blistering rash, but a National Institute of Health study suggests that psoralens can increase the risk of developing skin cancer.

Which fruits and vegetables have psoralens?

Psoralens are found in citrus fruits, including lemon and lime, as well as these fruits and vegetables:

• Anise seeds
• Caraway seeds
• Carrots
• Celeriac
• Celery
• Chervil
• Cilantro
• Coriander seeds
• Cumin seeds
• Dill
• Fennel seeds
• Figs
• Grapefruit
• Lovage
• Mustard seeds
• Parsley
• Parsnips
• Root parsley

Dr. Doris Day, a dermatologist in New York and clinical associate professor at NYU Langone Medical Center, told ABC News that the condition is fairly common and the skin can become more sensitive within an hour of being exposed to the psoralen.

“I see it every summer,” Day said.

Why is it called “Margarita burn?”

Phytophotodermatitis often happens after preparing citrus to be used in summertime drinks, according to Chicago dermatologist Dr. Carolyn Jacob.

Jacob says she shocks her patients who come to her with the rash by asking how many limes they sliced in making their margaritas.

“They say ‘Doctor, I have this weird rash,’ and I go ‘How many limes did you have in your margarita in Mexico?’” Jacob told ABC. “They gasp and say, ‘How did you know what I was doing?’”

How do you prevent the rash?

You should consider eating food and beverages that do not have psoralen if you are planning on being outside in the sun, according to the Mayo Clinic. If you do touch psoralen-containing fruits and vegetables, wash your hands thoroughly and reapply sunscreen to the area that touched the food.

If you can, use zinc oxide on the area – it blocks out more UVA rays. Also, physicians suggest you wear long-sleeved shirts or stay under shade or an umbrella.