What causes OAS?
Your body’s immune system helps keep you healthy by fighting off invaders like germs. When the body mistakes something harmless—such as dust or pollen—for an invader, it produces a substance that causes swelling, hives and sneezing. When this occurs, a person is said to have an allergy.
Pollen is the fine powder made by many plants. Up to 70% of people who have pollen allergies also have OAS.2 That’s because some of the proteins in fruit and vegetables are so much like proteins in the pollen, the body gets confused and causes an allergic reaction to the fruit or vegetable, too.
Which foods are linked to which pollens?
People with an allergy to 1 of the pollens listed below often get signs of OAS when they eat certain fresh fruits or vegetables such as:3
- Birch tree pollen: almond, apple, apricot, carrot, celery, cherry, hazelnut, kiwifruit, parsley, peach, peanut, pear, plum, soybean
- Alder tree pollen: almond, apple, celery, cherry, hazelnut, peach, pear, parsley
- Ragweed pollen: banana, cantaloupe, cucumber, honeydew, watermelon, white potato, zucchini
- Mugwort weed pollen: aniseed, bell pepper, black pepper, broccoli, cabbage, caraway, cauliflower, chard, coriander, fennel, garlic, onion, parsley
- Timothy and orchard grass pollen: orange, peach, tomato, watermelon, white potato
Allergic reactions to the foods are likely to happen more often and may be worse during the season in which the pollen is found.
What can you do if your doctor has diagnosed you with OAS?4
- It may be beneficial to cook the fruit or vegetable to break up the protein that causes the allergy. Most people who get OAS when they eat a raw apple, for example, have no problem eating it when it’s cooked.
- It may be helpful to peel the fruit or vegetable.
- A medicine called an antihistamine can help if you have an allergic reaction.
- If your OAS is causing big problems, your doctor might give you allergy shots for the related pollen.
If the symptoms are severe, it is a good idea not to eat the raw fruit or vegetable at all. Some allergic reactions can be severe. Get to the emergency room if you have low blood pressure, vomiting, diarrhea or trouble breathing.