Oral Allergy Syndrome: When Seasonal Allergies Cause Food Allergies

If you have seasonal allergies and experience an itchy throat or mouth after eating certain raw fruits or vegetables or tree nuts, you might be suffering from Oral Allergy Syndrome. Although Oral Allergy Syndrome can affect young children, it primarily affects older children, teenagers, and adults. Foods that you could tolerate in the past now elicit an allergic response as your immune system confuses pollen allergens with the protein in certain raw foods.

Oral Allergy Syndrome: What are the symptoms?

Like its name, Oral Allergy Syndrome (OAS) causes an allergic reaction only in the mouth, lips, and throat of sensitized individuals after eating fresh or raw fruits and vegetables. The lips, mouth or throat may quickly become itchy or swollen after eating certain types of fresh fruit or vegetables. Some people may also experience itching or irritation in their eyes, gums, and nose. In rare cases, a highly allergic person may experience anaphylaxis - difficulty breathing or swallowing - that requires immediate medical attention.

Seasonal Allergy Set Up: Who's at risk?

If you suffer from asthma or hay fever, you may be at risk for OAS. Individuals who suffer from pollen allergies may also be at risk for OAS. Several seasonal allergens are responsible for OAS:

  • Birch Tree Pollen

  • Grass Pollen

  • Ragweed Pollen

  • Mugwort Pollen

More than half of individuals with Birch tree pollen allergies experience OAS. If you are allergic to Birch tree pollen, you may react to not only fresh fruits and vegetables, but also to certain nuts. While there is no specific test for OAS, your healthcare practitioner may recommend a blood test or an allergy skin test to determine pollen allergies.

Ways to Manage OAS

If you suffer from seasonal allergies and have experienced symptoms after eating fresh produce, you should see your healthcare practitioner to determine if you have OAS. The type of pollen allergy you experience may make you sensitive to specific categories of fruit or vegetables or nuts. Here are a two of the pollen allergies and the foods that elicit OAS:

  • Birch Pollen Allergy (Sping): Apples, apricots, cherries, peach, pear, plum; kiwi; carrots, celery, parsley; soybeans, peanut; hazelnut, almonds.

  • Mugwort (Fall): Bell pepper, broccoli, cabbage, cauliflower, Swiss Chard, garlic, onion, parsley, anise, coriander, caraway, fennel, black pepper.

The good news is that with proper professional guidance, you can manage OAS. In fact, some individuals with OAS, can eat the same trigger foods if they are cooked. Since not everyone with OAS reacts to the same foods, proper allergy testing is important in identifying those individuals who reacts to raw versus cooked produce.

If you think you may have OAS and have questions about your next steps or are interested in learning more about this condition, please contact us.


Cudowska, B. Pollen-related food allergy in children with seasonal allergic rhinitis. Postepy Dermatol Alergol. 2021 Feb;38(2):96-101.

Oral Allergy Syndrome (OAS) | Children's Hospital of Philadelphia (chop.edu)

Oral Allergy Syndrome Symptoms, Diagnosis & Treatment | AAAAI

The contents of this blog are intended for educational purposes only. The information presented here is not a substitute for proper medical attention, diagnosis, or treatment by a qualified healthcare professional. Always seek the advice of your healthcare provider before starting or making any changes to an existing treatment plan, exercise program or dietary regimen, and before using nutritional supplements.

~ Dr. Sarah Williams ~ Concord, Massachusetts ~

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