Exercise-Induced Bronchoconstriction in Non-Asthmatic Children with Moderate-to-Severe Persistent Allergic Rhinitis Undergoing Subcutaneous Allergen Immunotherapy: Prevalence and Risk Factors.

Objective: The aim of this study was to investigate the prevalence of exercise-induced bronchoconstriction and associated clinical risk factors in children in the early phase of subcutaneous allergen immunotherapy for moderate-to-severe persistent allergic rhinitis. Methods: This cross-sectional observational study included 62 children aged 6-18 years who were in the early phase of subcutaneous allergen immunotherapy for moderate-to-severe persistent allergic rhinitis. Patients with a diagnosis of asthma or asthma symptoms were excluded from the study. All participants underwent an exercise provocation test with spirometry in accordance with the recommendations of the American Thoracic Society and the European Respiratory Society. A decrease of ≥10% in FEV1 from baseline at any time point following exercise was defined as exercise-induced bronchoconstriction. Demographic characteristics, concomitant atopic diseases, laboratory parameters, nasal symptom scores and respiratory function tests were evaluated. Results: The median age of the patients was 14 (9-18) years, and 71% were male. Exercise-induced bronchoconstriction was detected in 21 (33.9%) patients following the exercise provocation test. Exercise-induced bronchoconstriction positivity was most frequently observed at the 15th minute post-exercise. A family history of asthma was significantly higher in the exercise-induced bronchoconstriction-positive group (23.8% versus 2.4%, p = 0.014). Furthermore, the baseline Visual Analogue Scale and Total Nasal Symptom Score were significantly higher in exercise-induced bronchoconstriction positive patients (p = 0.035 and p = 0.016, respectively). No significant differences were observed between the groups in terms of total IgE levels, peripheral eosinophil counts, multiple aeroallergen sensitization, and baseline spirometric parameters. Conclusions: The prevalence of latent exercise-induced bronchoconstriction was 33.9% among children with moderate-to-severe persistent allergic rhinitis without asthma symptoms who had initiated subcutaneous allergen immunotherapy. In particular, including an exercise provocation test in the assessment process for patients with a family history of asthma and a high nasal symptom score may contribute to the early diagnosis of subclinical lower airway involvement.