Sometimes our bodies get confused and think that the protein of certain fruits and vegetables look exactly the same as a tree, weed, or grass pollen. This is called “cross-reactivity.” When this happens, our body starts to treat that fruit/vegetable like an allergy, causing your throat or mouth to itch within a few minutes after eating. Rarely, symptoms can include tongue or lip swelling. Different fruits/vegetables can cause OAS depending on what pollen you’re allergic to. For example, if your throat itches after eating an apple or celery, you may be allergic to birch tree pollen.
You may find that this happens with foods that never made you itchy before, as this can occur after teenage years. You may also find that it only happens when the fruit/vegetable is raw, but does not happen when it is cooked. This is because the proteins become “denatured” or weakened with high temperatures. These symptoms may also occur more frequently during pollinating seasons (spring, summer, or fall).
So what do you do about this?
It is very important to distinguish OAS from a true food allergy that requires epinephrine. You should see your allergy provider if:
- Your OAS symptoms are causing significant throat discomfort;
- Your OAS symptoms are getting progressively worse;
- Your OAS symptoms are caused by cooked fruits and vegetables;
- Your OAS symptoms are caused by nuts;
- You have ANY other symptoms other than an itchy throat after eating raw fruits or vegetables, such as facial swelling, hives, vomiting or difficulty breathing.
If you have symptoms of OAS, you can avoid eating these raw foods, especially during allergy seasons. You can also bake or microwave the food to weaken the proteins, or eat the canned version of the food. Also, peeling the food before eating may be helpful, as the offending protein is often concentrated in the skin of the fruit/vegetable. Allergy shots can also improve the symptoms of OAS, since allergy shots change your immune system to make you less allergic to pollen. Allergy shots are a great treatment option if you’re tired of feeling itchy after your favorite fruit or veggie!
Examples of possible oral allergy relationships are:
- Ragweed- bananas, melons, zucchini, cucumber, chamomile
- Birch- apples, pears, peaches, apricots, cherries, plums, almond, hazelnut, nectarines, kiwi, carrot, celery, parsley, caraway, federal, coriander and anise seed, soybean, peanut
- Grass- peaches, celery, melons, oranges
- Latex- bananas, avocado, kiwi, chestnut, papaya
A more complete list can be found at the link below: https://www.aaaai.org/Aaaai/media/MediaLibrary/Images/Conditions/Library/OAS-table_revised.pdf