Oral Allergy Syndrome (OAS) Defined
The proteins found in some fruits and vegetables are very similar to those found in particular pollen. These proteins can confuse the immune system in people with food or outdoor allergies. The result is called oral allergy syndrome (OAS) also known as pollen fruit syndrome (PFS).
For instance, if you are allergic to birch tree pollen, a primary airborne allergen responsible for symptoms in the springtime, you may have reactions triggered by peach, apple, pear, kiwi, plum, coriander, fennel, parsley, celery, cherry and carrot.
The most frequent reaction involves itchiness or swelling of the mouth, face, lip, tongue and throat. Symptoms usually appear immediately after eating raw fruits or vegetables, although the reaction can occur more than an hour later.
Rarely, OAS can cause severe throat swelling or anaphylaxis in a person who is highly allergic. Learn more about OAS and view a chart of additional triggers.
Learn more about food allergy symptoms, diagnosis, treatment and management.
Learn more about outdoor allergy symptoms, diagnosis, treatment and management.
Video: What is an oral allergy syndrome? »
If your symptoms are making you miserable, an allergist / immunologist, often referred to as an allergist, can help. An allergist has advanced training and experience to test which allergens are causing your symptoms and develop a treatment plan to help you feel better and live better.
The AAAAI's Find an Allergist / Immunologist service is a trusted resource to help you find a specialist close to home.