What is Oral Allergy Syndrome?

Oral allergy syndrome (OAS) is a condition that occurs in individuals who have pollen allergies, (also called hay fever or allergic rhinitis). People who have oral allergy syndrome experience symptoms when they eat foods, specifically, raw fruits and vegetables, that contain similar proteins to the pollen they are allergic to. Oral allergy syndrome is also sometimes called pollen-food allergy syndrome.

Oral allergy syndrome afflicts approximately one third of individuals who also suffer from pollen allergies. In addition to pollen allergies, some people who are allergic to latex may also experience OAS. Latex is a natural rubber that is derived from plants. Oral allergy syndrome is the most common type of food allergy in adults but may occur in individuals of all ages.

Symptoms of Oral Allergy Syndrome

The symptoms of oral allergy syndrome are very similar to that of traditional food allergies and the two conditions are often confused. Someone with OAS may experience itching inside of the lips mouth or throat when eating a triggering food. For most individuals the itching stops shortly after the food is swallowed but others may experience more severe symptoms such as hives or swelling of the lips mouth or throat. In severe cases a life threatening anaphylactic reaction can occur, (approximately 1.7% of cases).

Some individuals with OAS may also experience itching or redness of their hands when handling triggering foods.


Certain foods are known to trigger the symptoms of OAS in individuals who suffer from associated pollen allergies.

Ragweed Allergies 

Individuals who are allergic to ragweed may experience symptoms of OAS when eating: bananas, honeydew, cantaloupe, watermelon, tomatoes, cucumber, zucchini, sunflower seeds, dandelions, chamomile, and echinacea.

Birch Pollen Allergies

If you have birch pollen allergies you may experience symptoms of OAS when eating: kiwi fruit, apples, pears, carrots, celery, cherries, peaches, plums, almonds, hazelnuts, fennel, or parsley.

Grass Allergies

Individuals who are allergic to grasses may experience symptoms of OAS when eating: peaches, celery, melon, tomatoes, and oranges.

Latex Allergy

If you are allergic to natural rubber latex you may also have a reaction when eating: bananas, avocado, kiwi, chestnut or papaya.

Diagnosing Oral Allergy Syndrome

A diagnosis of oral allergy syndrome is best made by a specialized doctor called an immunologist. An immunologist will likely ask you for a detailed history of your symptoms and may conduct allergy tests such as skin prick testing.

Treating Oral Allergy Syndrome

Avoiding the foods that trigger symptoms of OAS is an important part of treatment. People with mild symptoms may be able to eat foods that would normally trigger symptoms after the foods have been cooked but not raw.

That's because cooking may help to denature the proteins in these foods. Other ways of preparing these foods such as microwaving, removing the skins, or eating canned foods may also help. Extreme caution should be used however since some individuals become more sensitive (and symptoms get worse) with repeated exposure to an allergen. You may also wish to discuss the possibility of immunotherapy (allergy shots) with your physician as a treatment.


American Academy of Allergy, Asthma and Immunology. Oral Allergy Syndrome. Accessed: February 28, 2015 from http://www.aaaai.org/conditions-and-treatments/library/allergy-library/outdoor-allergies-and-food-allergies-can-be-relate.aspx

American College of Allergy Asthma and Immunology. Oral Allergy Syndrome. Accessed: February 28, 2015 from http://acaai.org/allergies/types/food-allergies/types-food-allergy/oral-allergy-syndrome

Asthma and Allergy Foundation. Oral Allergy Syndrome. Accessed: February 28, 2015 from http://www.aafa.org/display.cfm?id=9&sub=20&cont=728

Uptodate. Oral allergy syndrome. Accessed: February 28, 2015 from http://www.uptodate.com/contents/oral-allergy-syndrome-beyond-the-basics

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