2. The experts also note that some people with seasonal allergies, particularly to grass or birch trees, may also suffer from allergies to closely related fruits, vegetables and nuts. About one in five people with grass allergies and as many as 70 percent of people with birch allergies have these cross-reactions, known as pollen food allergy syndrome.
3. People with allergies to birch or alder trees may experience tingling, itching and swelling around the mouth when they eat celery, cherries or apples. People with grass allergies sometimes find tomatoes, potatoes or peaches problematic.
Although often not serious, reactions to these foods can be life- threatening in a small percentage of people. A life-threatening allergic reaction is called anaphylactic shock, and high-risk people should carry a portable epinephrine pen.
Allergists also encourage people to take their medicine even before their symptoms flare, and to see an allergist who can suggest the best course of treatment.