The functional connection between oral allergy syndrome and united airways disease assessed by oral challenge

Abstract 

Background

The airways and the upper digestive tract have a common embryonic origin. In sensitized subjects they can respond to allergens with an immediate reaction (asthma, rhinitis, or oral allergy syndrome [OAS]).

Objective

To investigate the possible functional connection between respiratory and upper digestive tract by means of specific oral allergen challenges.

Methods

Patients sensitized to birch and apple were subdivided into group A (n = 12; asthma + rhinitis caused by birch and OAS caused by apple); group B (n = 10; OAS caused by apple without asthma/rhinitis); group C (n = 8; asthma and rhinitis caused by 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

No change occurred 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 seen in either forced vital capacity or forced expiratory volume in 1 second.

Conclusion

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