Kingston Allergy and Asthma

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

• 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