This was previously called Oral Allergy Syndrome (OAS), the term was coined to define the symptoms. It has now been termed Pollen Food Allergy Syndrome (PFAS) more definitively as it mostly affects people who already suffer from pollen allergies and seasonal rhinitis due to cross reactivity.
In PFAS the body mistakes the shape of a protein that it is already sensitive to (a plant pollen) to a similarly shaped protein in certain fruits, vegetables, spices, herbs, and nuts.
The key allergen in PFAS is the pollen associated with the group of foods you are having symptoms from eating.
You may have Pollen-Food Allergy Syndrome if you suffer from oral allergy symptoms to 3 or more of the foods mentioned in cross reactivity section.
If sensitised to Alder pollen you may also react to Apple, Cherry, Peach, Pear, Parsley, Celery, Almonds, and Hazelnuts.
If sensitised to Birch pollen you may also react to Apple, Kiwi, Pear, Peach, Plum, Nectarine, Apricots, Cherries, Tomato, Celery, Carrot, Potato, Parsnip, Pepper, Dill, Cumin, Peas, Coriander, Fennel, Hazelnut, Walnut, Almonds, Peanuts, Lentils and Beans.
If sensitised to Grass pollen you may also react to Melon, Watermelon, Tomatoes, Oranges, Potatoes and Peanuts.
If sensited to Mugwort pollen you may also react to, Apple, Celery, Carrots, Dill, Parsley, Fennel, Coriander, Cumin, and Sunflower seeds.
If sensitised to Ragweed pollen you may also react to Watermelon, Banana, Courgette, Cucumber and Squash.