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If you experience itching and swelling after eating a variety of fresh fruits and vegetables, you may be dealing with oral allergy syndrome.

If you experience itching and swelling after eating a variety of fresh fruits and vegetables, you may be dealing with oral allergy syndrome.

"An apple a day keeps the doctor away," or so says the old proverb, but for people who live with oral allergy syndrome, biting into a fresh apple could lead to more time at their physician's office instead of less. 

Sometimes called pollen-food allergy, OAS may affect people who have strong hay fever allergies, according to the American Academy of Allergy, Asthma and Immunology. For these individuals, their sensitivity to certain pollens can be so severe that even eating fruits, nuts and vegetables that grow from plants with these pollens can cause an allergic reaction. 

If you've ever felt itching, swelling or tingling in your mouth and throat after eating fresh produce, there's a chance you may be experiencing OAS.

"The effects of OAS are strongest when food is raw."

Which foods can trigger an OAS reaction?
Many different raw foods have the same pollen in common. An allergy to one type of plant may lead to food allergies from any product that comes from that group, while others may be perfectly safe. The American College of  Allergy, Asthma and Immunology explained that people with an allergy to birch pollen are more likely to have reactions to foods like apples, almonds, peaches and pears, whereas those with a ragweed allergy will feel effects from bananas, cucumbers and melons.

The effects of OAS are strongest when food is raw, however. Many people who are have allergic reactions to raw fruits and vegetables are able to eat them when they've been cooked or significantly processed, as the triggering pollen enzymes break down in the process. 

What are the symptoms of OAS?
The good news for most people who have OAS is that while the reactions are uncomfortable, they aren't typically dangerous. As a result, it can take some time for people to realize that they have the food allergy.

Symptoms are typically confined to:

  • Itching of the mouth, tongue, cheeks and throat immediately after ingesting the allergen. 
  • Swelling in the throat and mouth after contact with the triggering food. Usually swelling is mild, but in rare cases in can be more extreme. 

It's important to note that symptoms that progress beyond these could signal the development of a more serious allergy that could lead to anaphylaxis. Hives, vomiting or allergic reaction to multiple types of nuts are all signs of a more dangerous condition. OAS, on the other hand, usually doesn't require any medical intervention.  

Though OAS may be mild and non-fatal, you should still use caution and avoid any of the foods you've had a previous reaction to, and tell your doctor if symptoms get worse or persist even after the food has been cooked. 

Avoid any fruits or vegetables that have caused you to have an OAS reaction before. Avoid any fruits or vegetables that have caused you to have an OAS reaction before.

Getting the right nutrition when you have OAS
There is no cure or treatment for OAS – the only way to prevent reactions is to avoid eating the foods that cause them. Symptoms begin immediately after contact with the food, so it's important to pay attention to what you're eating to determine which products to rule out. Because fruits and vegetables are integral parts of a healthy, balanced diet, especially when consumed raw, having OAS can make it more difficult to get the proper vitamins and minerals you need to stay nourished. 

In a report for UpToDate, Marion Groetch, director of nutrition services at the Jaffe Food Allergy Institute, stated that dietary restrictions caused by food allergies can lead to malnutrition and impact healthy weight gain for young children. 

To maintain the right diet while living with OAS, you should consult your doctor for help constructing a nutrition plan. You may be advised to incorporate new foods into your meals, or to try dietary supplements to help you get all the vitamins that you need to stay healthy.