April 13, 2023—If your mouth or throat has ever become itchy after eating raw fruits or vegetables, you may suspect a food allergy. But there might be another explanation: oral allergy syndrome (OAS).
OAS, sometimes called pollen fruit syndrome or pollen food allergy syndrome, is the result of your immune system becoming confused when you eat certain raw fruits and vegetables. The proteins in these foods are similar to those in some trees and grasses. Your immune system identifies the food protein as an allergen and produces a reaction. This is called cross-reactivity.
The food-plant connection
According to the American Academy of Allergy, Asthma & Immunology, people with OAS have reactions to different foods based on the type of seasonal allergies they have. For example, if you are allergic to birch trees, you may experience OAS when you eat pitted fruit, carrots or celery. If you have a ragweed allergy, you may notice symptoms when you eat melons or bananas.
OAS symptoms
When you eat a food that triggers OAS, you might experience symptoms such as:
- Itching and tingling of the mouth, the throat and sometimes the lips.
- Slight swelling and bumpiness of the mouth, throat or lips.
- Redness, itching or mild swelling of the hands when handling OAS-causing raw fruits and vegetables.
- In rare cases, a person can develop sudden, severe symptoms elsewhere in the body, such as hives, vomiting or difficulty breathing. This is called anaphylaxis, and it can be serious—even deadly.
OAS symptoms begin within a few minutes of eating the trigger food. They disappear shortly after swallowing because your stomach acids easily destroy OAS-causing allergens. Cooking or heating foods also destroys the allergens, so it's a great way to enjoy those foods without experiencing OAS symptoms.
When to seek medical attention
OAS is typically mild and doesn't require treatment. But true food allergies can be serious. If you're not sure which you're experiencing, talk to your doctor. You should also see a doctor if your symptoms:
- Become progressively worse.
- Are caused by eating cooked fruits and vegetables.
- Are caused by eating nuts.
- Give you significant throat discomfort.
- Are severe and develop in other areas of your body besides your mouth and throat.
Your doctor or allergy specialist can determine if your reaction is OAS or an actual food allergy. And if pollen allergies like the ones that cause OAS are affecting you, it may be time to consider long-term allergy treatment. Our interactive tool can help you decide if it's right for you.
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