IGHE and seasonal allergic rhinitis: Among allergy patients in Korea, 20% of those with a positive response to birch pollen allergen on the skin prick test had oral allergy syndrome20; of the participants positive for birch pollen IgE, 49.6% had a history of allergic rhinitis/hay fever, and 23.6% of participants negative for birch pollen had a history of allergic rhinitis/hay fever.