What Is OAS?

Peaches, melons, corn, cherries and cucumbers are hands down some of the seasonal fruits and vegetables that we look forward to eating during summer. While these summertime favorites are enjoyable for most, others may experience itchiness of the mouth or other discomforts after consuming them. This reaction may be due to a condition known as oral allergy syndrome (OAS).

According to the American Academy of Allergy Asthma and Immunology, OAS is defined as “a form of contact allergy reaction that occurs upon contact of the mouth and throat with raw fruits or vegetables.”   This happens because your body is unable to tell the difference between proteins in these foods and pollen. “The immune system recognizes the pollen and similar proteins in the food and directs an allergic response to it,” states the American College of Allergy, Asthma and Immunology.  Therefore if a person is allergic to pollen there is a chance they can develop OAS.

Most cases of OAS are attributed to an allergy to birch pollen. Those who are allergic to birch pollen may experience symptoms when eating fruits or vegetables such as cherries, zucchini, peaches and plums.  Allergies to other types of pollen from grass or ragweed may trigger a reaction when consuming produce such as melons, cucumbers or bananas.

Symptoms of OAS are typically mild and last for only a few minutes; they may include:

  • Itching
  • Tingling
  • Redness
  • Mild swelling of the lips or tongue
  • Irritation of the throat and gums

In most cases these symptoms do not need treatment as they resolve in minutes.  Avoidance of trigger foods is highly recommended; however, if you must have a fruit or vegetable, consider peeling or cooking it to potentially lessen the reaction.  These recommendations may not work for everyone because each person’s tolerance is different.

OAS is diagnosed by an allergy specialist who will conduct an evaluation.  The specialist may recommend skin testing to pollens or other allergens that may be causing your symptoms.  It is also possible that your allergy specialist will ask you to eat certain foods while observing your reaction; this is called a food challenge.

It is important to keep in mind that OAS is a cross reaction to pollen rather than an allergic reaction to the actual fruit itself. The symptoms of a true food allergy can be more severe and can lead to anaphylaxis. The following symptoms should not be ignored and receive medical attention immediately:

  • Vomiting or stomach cramps
  • Shortness of breath
  • Hives
  • Shock
  • Tightness of the throat or trouble swallowing
  • Dizziness

The Division of Allergy and Immunology at Jamaica Hospital Medical Center focuses on the diagnosis and long-term treatment of allergic and immunologic conditions. To speak with an Allergy Specialist at Jamaica Hospital about OAS or food allergies, please call 718-206-6742

All content of this newsletter is intended for general information purposes only and is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. Please consult a medical professional before adopting any of the suggestions on this page. You must never disregard professional medical advice or delay seeking medical treatment based upon any content of this newsletter. PROMPTLY CONSULT YOUR PHYSICIAN OR CALL 911 IF YOU BELIEVE YOU HAVE A MEDICAL EMERGENCY.