If patients are allergic to one food, they may also show reactivity to other foods belonging to the same biological family. Foods contain a lot of different allergens, and a patient may be sensitized to one or a few of these. Furthermore, one food might contain the same allergen as another, although it is never certain that a patient will react clinically to both foods. The most well-documented cross-reactivity is the one which occurs between apple and birch pollen. Nevertheless, all apple allergics are not necessarily allergic to birch pollen. Cross-reactivity can never be assumed. Under no circumstances should important foods be eliminated from the diet without appropriate testing and clinical diagnosis.

 

The following are examples of claimed cross-reactivities based on studies with immunochemical methods and/or clinical diagnosis. (List of literature references can be supplied on request.)