Ask the Allergist: Food Allergy or Oral Allergy Syndrome?



Q: People with pollen allergy sometimes feel an allergic reaction after eating certain fruits, vegetables or nuts. Is this a food allergy or something else?

Maeve O’Connor, MD: It could be a food allergy, but it’s likely oral allergy syndrome. It happens when a patient with pollen allergy experiences a cross reaction to certain foods. What’s behind it are protein similarities in pollen-producing trees, grasses and weeds and related fruits and vegetables.

For example, between 50 to 75 percent of patients with birch tree pollen allergy may experience symptoms of oral allergy syndrome such as itchy mouth, sore throat, swollen lips or throat or an uneasy feeling in their stomach after eating pitted fruits such as peaches, plums, apricots or cherries. Usually this is a mild cross reaction, but symptoms may get worse during pollen season. It could represent a more serious problem such as a true food allergy.

If you have these symptoms, I recommend seeing a board-certified allergist to determine whether the symptoms are simply a cross reaction or whether it could lead to a life-threatening allergic reaction such as anaphylaxis. If it’s anaphylaxis, this may require the use of an epinephrine auto-injector for treatment and an Anaphylaxis Action Plan.

Patients with oral allergy syndrome can also minimize and even avoid symptoms altogether by doing just a few simple things:

  1. Avoid the food that is causing symptoms
  2. Bake or microwave the food before eating – this breaks down the allergic protein and then patients are able to tolerate it
  3. Peel the skin off fruits that cause symptoms

Q: What are some common foods that trigger oral allergy syndrome?

Dr. O’Connor: Specific foods that relate to birch, grasses and ragweed include the following:

  • Birch pollen: almond, apple, carrot, celery, cherry, hazelnut, kiwi, peach, pear, plum, potato, pumpkin seed
  • Grass pollen: kiwi, melon, peach, tomato
  • Ragweed pollen: banana, chamomile, cucumber, echinacea, melon (watermelon, cantaloupe, honeydew), sunflower seed, zucchini

Maeve O’Connor, MD, FACAAI, is a board-certified allergist and immunologist with Allergy, Asthma & Immunology Relief (AAIR) in Charlotte, North Carolina. She serves on the Board of Regents with the American College of Allergy, Asthma & Immunology (ACAAI).


Have a medical question? Email editor@allergyasthmanetwork.org or write to Ask the Allergist, Allergy & Asthma Network, 8229 Boone Blvd., Suite 260, Vienna, VA 22182. 


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