Oral Allergy Syndrome


If you suffer from pollen allergies, and you also notice that your mouth and throat become itchy after eating certain fruits and vegetables, there is a good chance you may have oral allergy syndrome, also known as OAS. The reaction is the result of a cross-reactivity in which the body confuses the proteins found in raw fruits and vegetables with similar proteins found in the pollen of certain trees, weeds, and grasses. The proteins trigger the body’s immune system, which initiates an allergic reaction or exacerbates existing allergy symptoms.

OAS Symptoms:

OAS reactions are generally mild and short-lived. Individuals with OAS typically experience swelling and itchiness of the lips, mouth, tongue, throat, and face. In most cases, the symptoms will begin immediately after eating specific raw fruits and vegetables; however, it may be possible for symptoms to appear as long as an hour after eating. OAS can occur at any time of year, but the symptoms may be slightly worse during pollen allergy season.

Suspect Foods:

Depending on your particular pollen sensitivity, one or more foods may trigger OAS symptoms. The following are some of the most common pollen allergies along with a few of the foods that may cause OAS symptoms:

• Birch allergies: Apples, celery, kiwi, carrots, and apricots.
• Ragweed allergies: Bananas, cantaloupe, honeydew, and watermelon.
• Grass allergies: Celery, oranges, peaches, and tomatoes.
• Mugwort allergies: Celery, carrots, apples, bell pepper, and cabbage.

It is important to note that only plant-based foods will cause OAS symptoms. If you experience similar symptoms when you eat nuts, you should consult an allergist since it could indicate a more serious food allergy.


Antihistamines and allergy shots may help alleviate OAS symptoms; however, the best treatment is to avoid your trigger foods. Peeling, cooking, or eating canned fruits and vegetables may also help limit your reaction. You should consult an allergist if your symptoms worsen, cause significant discomfort, or are caused by cooked fruits or vegetables.

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