Oral Allergy Syndrome

Also known as: OAS, pollen-food syndrome.

What is oral allergy syndrome?

Oral allergy syndrome is a type of food allergy where the allergic reaction only affects the lips, mouth and throat. It usually occurs in adults but can affect children, particularly when they have hay fever or asthma.

What causes oral allergy syndrome?

Oral allergy syndrome symptoms occur when a child who is allergic to pollen eats some raw fruits or vegetables and the body’s immune system mistakenly reacts to the similar pollen proteins (cross-reactivity) found in pollens.

Common culprits include apples, almonds, celery, cherries, cucumbers, tomatoes, carrots and many other fruits and vegetables. Symptoms tend to be worse during pollen season.

What are the symptoms of oral allergy syndrome?

Symptoms of oral allergy syndrome normally appear within a short time of eating the raw, dried or dehydrated food with redness, swelling, itchiness and/or burning of the lips, mouth or throat.

Symptoms tend to be less severe compared to other food allergies and anaphylaxis (e.g. hives, nausea and vomiting and/or diarrhea, breathing problems, drop in blood pressure and bluish color of lips, mouth, skin and nail beds) is rare.

What are oral allergy syndrome care options?

Cooking may break down some of the proteins associated with OAS and canned, processed, pasteurized or frozen foods may be safe. Avoiding the particular food(s) is best. Treatment is typically not needed for oral allergy syndrome, however over-the-counter antihistamines may be useful.

Severe recurrent OAS may warrant “allergy shots” (immunotherapy).


Reviewed by: Jack Wolfsdorf, MD, FAAP

This page was last updated on: May 12, 2021 09:18 AM

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