Oral Allergy Syndrome and United Airways Disease: Is There a Functional Connection?

Background: The airways and the upper digestive tract have a common embrional origin, and in sensitized subjects they can respond to allergens with an immediate reaction (asthma, rhinitis or oral allergy syndrome). We investigated the possible functional connection between respiratory tract and upper digestive tract by means of specific oral allergen challenges.

Methods: Patients sensitized to birch and apple were subdivided in GROUP A (N= 12; asthma  and rhinitis due to birch and OAS due to apple) GROUP B (N= 10; OAS due to apple without asthma/rhinitis);  GROUP C (N= 8; asthma and rhinitis due to birch without OAS). Healthy subjects represented the control group D (N= 6). Oral provocation test with apple was performed out of the pollen season. Visual analog scale for eye, nose and mouth symptoms, spirometry, nasal eosinophil count and exhaled nitric oxide were assessed before and 6 hours after challenge.

Results: There was no change in nasal and ocular symptoms before versus after challenge in all  groups. On the contrary, in groups A and B the oral scores significantly increased after challenge (p<.001), whereas no change was seen in groups C and D. Exhaled nitric oxide and nasal eosinophils showed no change before versus after challenge in all groups. Nitric oxide was higher before and after challenge in groups A and C vs groups B and D. No change was een as well in forced vital capacity and forced expiratory volume in one second.

Conclusions: In the case of birch-apple syndrome, eating apple does not functionally or clinically affect the respiratory tract.