The impact of aeroallergen sensitization on bronchial hyperreactivity in adults

Background: Although the relationship of seasonal allergens with allergic rhinitis is well known, conflicting results exist with regard to their association with asthma. Objective: To investigate the effect of seasonal allergen sensitization on the severity of bronchial hyperreactivity (BHR) and variables that affect BHR in individuals without any chronic respiratory disease who presented to the outpatient clinic with asthma symptoms. Methods: Adult subjects who were admitted to our hospital's allergy outpatient clinic between January 2016 and May 2023, presented with at least one of the symptoms of dyspnea, wheezing or cough, and underwent bronchial provocation test (BPT) for the differential diagnosis of asthma were included in the study. Patients with any chronic respiratory disease, such as chronic obstructive pulmonary disease (COPD) or bronchiectasis, were excluded. Demographic characteristics and clinical features of the patients, including admission symptoms, BPT results, skin-prick test results, IgE results, and allergy history were obtained by reviewing patient records. Results: A total of 325 patients were included in the study, 248 (76.3%) of whom were women, and the median (min-max) age was 40 years (18-82 years). Aeroallergen sensitization was positive in 131 patients (40.3%), of whom 38 (11.7%) had single and 93 (28.6%) had multiple allergen sensitization. Sensitization was to perennial allergens in 53 patients (16.3%), to seasonal allergens in 40 patients (12.3%), and to both in 38 patients (11.7%). BPT was positive in 105 patients (32.3%). Among the patients with BHR, 73 (69.5%) had at least one allergen sensitization. The BHR risk was 7.13 times higher in patients sensitized to perennial allergens, 4.14 times higher in those sensitized to seasonal allergens, and 8.67 times higher in patients with sensitization to both. There was no significant difference in PC20 values according to the type of allergen sensitization (perennial allergens, seasonal allergens, mixed type) (p = 0.878). Conclusion: Both seasonal and perennial allergens can elevate the risk of BHR.