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Oral allergy syndrome (OAS) is a common food-related allergy that is caused by cross-reacting allergens found in pollen, raw fruits, vegetables, and tree nuts. The pollen of some trees and grasses are similar to the proteins found in certain raw fruits, vegetables, and nuts. When one has OAS, the body confuses a food protein with pollen, causing an allergic reaction.  


The symptoms of OAS tend to be concentrated in the mouth and/or throat. When OAS is triggered, one may experience the following symptoms:

  • Scratchy throat
  • Sneezing and nasal congestion
  • Swollen or numb lips
  • An itching or tingling sensation on the tongue

If allergy symptoms occur outside of these listed symptoms or outside of the mouth and/or throat, these may be signs of a more serious allergic reaction warranting emergency care. 


OAS only happens as the result of cross-reactivity between pollen and similarly structured proteins in certain fruits, vegetables, and tree nuts. Common triggers and foods they cross-react with include:

  • Birch pollen: almond, apples, kiwi, apricot, banana, pear, soybean
  • Grass pollen: peas, beans, tomato, orange, celery, carrot, zucchini
  • Ragweed pollen: melons, banana, sunflower seeds, zucchini, cucumber


The most common way to manage OAS is by avoiding the above food in raw forms. If the food cannot be cooked, one may choose to completely avoid eating those foods. Other treatment options include:

  • Over-the-counter antihistamines, such as Benadryl or Allegra
  • Immunotherapy 
  • Epinephrine auto-injector

Many allergy-related symptoms can be managed with over the counter medicines, prescription medications, and environmental avoidance strategies if the allergies are known. With allergy skin testing and/or blood testing, we can discover hidden triggers, confirm suspected triggers, and provide additional treatments, including immunotherapy if appropriate. 

Contact Northeast Allergy, Asthma & Immunology today to schedule your appointment.

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