Have you ever taken a bite from an apple and felt your mouth get itchy? Did a tasty banana cause your tongue to swell? If so, chances are you have oral allergy syndrome, or pollen-food allergy syndrome as it’s also known. It happens because your immune system can’t tell the difference between proteins in these foods and pollen. The symptoms are usually itching, tingling, and swelling, mostly to the mouth, lips, and throat.

You Can Have It and Not Know It

Oral allergy syndrome is common, says Robert Eitches, MD, attending physician at Cedars-Sinai Medical Center. He says he has about 500 patients who have it.

But many who have it don’t know they do. A lot of people with pollen allergies know they can’t tolerate these foods, but they don’t make the connection between them and their allergies, he says.

People find out when their allergy testing is negative for foods but positive for something like birch pollen, grass pollen, or ragweed pollen, Eitches says.

"We’re just learning about the syndrome over the last 5 or 10 years," Eitches says. "I think it’s been around longer than we realized. It’s become more obvious in the last 2 or 3 years."

Who Gets It?

Oral allergy syndrome mostly affects teens and adults, though younger children sometimes get it, too.

In most cases the reactions are mild and don’t last long. Symptoms usually show up right after you eat. But it could take up to an hour.

What If My Reactions Are Severe?

Treat it like a pollen allergy. Antihistamines, epinephrine (for severe reactions) and immunotherapy are three courses of action. But there isn’t a specific medication to treat oral allergy syndrome.

In rare cases, it can cause a life-threatening reaction known as anaphylaxis. Symptoms may include:

Shortness of breath

Tightness in your throat

Hives

Vomiting

Nausea

Diarrhea

Dizziness

Call 911 if you have any of these signs.

Your doctor can tell you if you’re at risk for anaphylaxis. He may prescribe an epinephrine auto-injector.