Oral Allergy Syndrome (OAS)

Also known as: Pollen-Food Allergy Syndrome

OAS happens when your immune system confuses proteins in certain raw, fruits, vegetables, or nuts with pollen allergens (like birch, ragweed, or grass). The proteins are similar, so your body reacts-even though the food itself isn’t a “true” food allergy.

Common Symptoms

  • Itchy or tingly mouth, lips, tongue, throat

  • Mild swelling of lips or tongue

  • Scratchy throat - symptoms usually start within minutes of eating and often resolve quickly.

Common Cross-Reactions

  • Birch Pollen - apples, pears, peaches, cherries, carrots, almonds and hazelnuts

  • Ragweed Pollen - melons, watermelon, cantaloupe, banana, zuchini, cucumber and kiwi

  • Grass Pollen - peaches, tomatoes, oranges

Why cooking helps - heat changes the protein structure, so many people with OAS can eat the cooked or baked version safely.

How is OAS is diagnosed - strong history of seasonal allergies. Symptoms only with raw foods. Allergy testing may show pollen sensitivity. Note: food skin tests can be falsely positive.

DISCLOSURE - This is content is provided by Allergy & Immunology Associates of New England (AIANE) for general informational purposes only. It is not intended to replace individualized medical advice, diagnosis, or treatment. Symptoms, reactions, and management plans vary by patient. Always consult a qualified allergy and immunology specialist for personalized care.

SCHEDULE AN APPOINTMENT - if you suspect Oral Allergy Syndrome (OAS) or have questions about food reactions, seasonal allergies, or immunotherapy, our team is here to help.

Allergy & Immunology Associates of New England (AIANE) Phone: (855) 763-3998

  • Serving patients across the nation.

  • In-office and telehealth consultation available.