Do you ever get a tingling, itchy, or scratchy tongue or throat after eating certain raw fruits, vegetables, nuts, or seeds? You aren't alone. In fact, there's actually a term for this: oral allergy syndrome (OAS).
OAS is caused by a cross-reactivity between foods and pollens, and people who experience OAS usually also have seasonal hay fever symptoms as well.
What happens is that the proteins in the foods look similar enough to the pollen proteins that your immune system causes an allergic reaction (or makes an existing one worse). Usually the symptoms are mild, localized, and dissipate pretty quickly — but they can cause enough discomfort to make you want to avoid that food.
The most common pollens that cause this cross-reactivity are from birch, ragweed, or grasses. Since the pollen production of these plants is seasonal, OAS symptoms can often increase or decline as the seasons change too. These are some of the most common foods that can cause OAS: