Oral Allergy Syndrome (OAS)
Definition:
- Patient is allergic to birch, grass or ragweed pollens which contain a protein found in many plants therefore cross reacting with a variety of fruits and nuts
- Not actually allergic to the fruits or nuts themselves
Pollen Cross-Reacting Foods
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Birch Almonds Kiwi
Apple Parsley
Apricots Parsnip
Carrots Peach
Celery Pear
Cherry Plum
Fennel Potato
Hazelnut Walnut
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Ragweed Banana Honeydew
Cantaloupe Watermelon
Cucumber Zucchini
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Grass Celery
Buckwheat
Potato
Melon
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Symptoms (to fresh fruits and nuts)
- Tingling/itchy mouth, lips, throat
- Possible throat tightening, lip swelling, itchy ears
- Can eat the foods cooked or processed
- Does not usually progress to anaphylaxis
- By clinical history mainly
- Skin testing to commercial extracts usually negative, but skin test positive on fresh food testing
- Skin test positive to cross-reacting pollen (birch, grass, ragweed)
- Avoid fresh fruit or nuts. May eat the fruits cooked or processed
- Usually does not require Epipen unless has symptoms of throat closing or other systemic symptoms or has positive skin test to the commercial extracts
*** Created by Dr. Ellie Tsai MD, FRCPC Kingston Allergy and Asthma 613-546-6673***