You may have oral allergy syndrome (also called pollen-food allergy syndrome). Some people also react to nuts or spices.

“Certain proteins in plant foods have similar structures to proteins in pollen,” explains Roxanne Oriel, physician and assistant professor of pediatrics, allergy and immunology at the Icahn School of Medicine at Mount Sinai Hospital in New York. So if you have hay fever, your immune system may mistake a food protein for a pollen protein.

Among the most common offenders: apples, peaches, melon, carrots, tomatoes, hazelnuts, and almonds.

In most people, the itching or swelling of the mouth, lips, or throat is mild and goes away on its own.

And many allergens that cause oral allergy syndrome are inactivated by heat. “I have patients who can’t eat a fresh apple, but apple pie or applesauce is fine,” says Oriel. “If the food is cooked or processed, they don’t have symptoms.”

But some allergens aren’t inactivated by heat and can cause more severe symptoms in some people with oral allergy syndrome. An allergist can help identify foods that are more likely to cause serious reactions.