Birch pollen allergy and food allergies

If a birch pollen allergy exists, certain foods are often not tolerated due to allergen cross-reactivity. The symptoms are usually mild, as the responsible allergens are relatively sensitive and are already broken down in the mouth by the saliva. Therefore, the symptoms are typically localized: itching or burning in the mouth and throat, or sometimes swelling of the mouth and throat, which can cause problems with swallowing. Hives or even asthma, indigestion, and circulatory problems are very rare.

This phenomenon is caused by a so-called "allergen family" between botanically related plant foods and pollen. More specifically, the same proteins found in pollen are found in various plant foods.