What is oral allergy syndrome?

Oral allergy syndrome (OAS, pollen-food allergy syndrome) is contact urticaria of the oropharynx http://bit.ly/HVvXf

OAS is caused by allergens in fruits, vegetables, tree nuts, and peanuts that are homologous to pollen allergens.


Cross-reactivity in Pollen-Food Allergy Syndrome (PFAS) or Oral Allergy Syndrome (OAS) (click to enlarge the image).

Cross-reactivity list in oral allergy syndrome (pollen-food allergy syndrome): http://bit.ly/dFuk1

Flavored Coffee May Trigger Seasonal Allergies - due to oral allergy syndrome. Fox News, 2011.

Which allergen cross-reacts with Bet v1 (birch)?

(A) Ara h1 (peanut)

(B) Mal d 1 (apple)

(C) Ara h3 (peanut)

(D) Bos d (milk)

(E) Gal d (egg)

(F) Hev b2 (latex)

Answer: B, apple. Pollen sensitizations linked to food allergies was first reported with birch pollen and apples 50 years ago.

Related:

Profilin may be a pan-allergen among plants that crossreacts between pollen, fruits, vegetables and latex http://goo.gl/ZUPRQ

Cross Reactions Among Foods (PDF).

Oral symptoms from the ingestion of food in a patient with allergic rhinitis - AAAAI Ask the Expert, 2011.
In birch-apple syndrome (oral allergy syndrome), eating apple does not affect the respiratory tract. Annals of Allergy, Asthma and Immunology, 2011.