Q: Over the past year, I started getting a terribly itchy mouth if I ate apples or pears or celery. Now carrots and potatoes, too! My doctor says this is a form of food allergy, related to my pollen allergies. Can you help me understand this? I’m concerned about what’s OK to eat.
Dr. Sharma: This sounds characteristic of “pollen food allergy syndrome” (also known as “oral allergy syndrome “). This is one of the most common forms of food allergy, especially in adults.
What happens is that a person with a prior history of a pollen allergy develops allergic symptoms, such as itchy and /or mild swelling of the mouth, lips and throat , when eating certain raw fruits and vegetables. This occurs because the immune system “sees” the raw fruit and vegetable as very similar to the pollen triggers, which the immune system is already primed to defend against.
Symptoms after eating apples and pears are often related to birch tree pollen allergy; celery and carrots are linked to birch tree or mugwort weed pollens; and potato relates to grass pollen. Symptoms may be worse during or after the related pollen season.
Fortunately, symptoms are usually confined to the mouth and throat and eating the implicated fruits or vegetables, while uncomfortable, would pose no significant risk. Fewer than 10 percent of patients have more widespread reactions and only 1 to 2 percent experience anaphylaxis.
Cooking these fruits or vegetables often breaks down the proteins, making them less allergenic. The good news is that there’s little chance your symptoms will become more widespread or dangerous, and they might have significantly lessened if the fruits and vegetables are cooked.
Dr. Sharma is an allergist, clinical researcher and Assistant Professor of Pediatrics. He is Associate Chief of the Division of Allergy and Immunology at Children’s National Medical Center in Washington D.C. and Director of the Food Allergy Program. He co-authors “The Food Allergy Experts” column in the American Edition of Allergic Living  magazine. Questions submitted below will be considered for answer in the magazine.