Ask the Doctor: What is Oral Allergy Syndrome?

Do fresh fruits and vegetables make your mouth, lips and tongue tingle and itch? Dr. Reynold M. Karr answers important questions about Oral Allergy Syndrome (OAS), a Class 2 food allergy that may affect individuals with pollen allergies.

What is Oral Allergy Syndrome (OAS) and who does it affect?

Oral Allergy Syndrome mostly affects people with seasonal pollen allergy, typically allergic rhinitis, which is the medical term for hay fever.

What are the symptoms of OAS?

Common symptoms of OAS are itching of the mouth and throat beginning almost immediately after the food enters the mouth. It may last a few minutes but rapidly resolves once the food is swallowed.

Can an Oral Allergy Reaction result in anaphylaxis?

While this is certainly possible, systemic or generalized reactions occur in less than 5-10% of people with this disorder, and a large portion of these reactions are not anaphylaxis.

Which foods cause OAS? Which pollen allergies are linked to which foods causing OAS?

OAS is most often caused by uncooked (raw) fruits, vegetables, nuts, and spices. Cooking the foods breaks down the allergens in the food and usually eliminates the OAS reaction. Common pollen-food associations include: Birch tree pollen with pitted fruits; grass with watermelon, orange, and tomato; ragweed with melons and banana; and mugwort (weed) with a variety of vegetables and spices. A detailed chart is available at the American Academy of Asthma, Allergy, and Immunology (AAAAI) website.

As an adult with hay fever, is there a possibility I will develop Oral Allergy Syndrome?

Yes, but it is less likely the older you are. For reasons that are not completely understood, the condition appears to affect only a minority of hay fever sufferers, although it may be under-reported since mild reactions cause minimal annoyance and are often ignored.

Reynold M. Karr, M.D., is a board certified physician at UW Medical Center’s Allergy, Asthma and Immunology Clinic. He is also the medical director of PlasmaLab International in Everett.

Do you experience Oral Allergy Syndrome? You may qualify to donate plasma for allergy research.

Compensation is $185 per completed plasma donation.