Risk Factors and Asthma Phenotypes in Children and Adults with Seasonal Allergic Rhinitis

Abstract

Background: There are few data on asthma risk factors and phenotypes in patients with seasonal allergic rhinitis (SAR). Methods: Thirty-three children (mean age, 8.27 ± 1.77 years) and 82 adults (mean age, 34.12 ± 10.59 years) with SAR were evaluated for asthma (history, reversibility of bronchial obstruction, increased inhaled nitric oxide). The following asthma risk factors were considered in the multiple regression analysis: male sex, family history of asthma, breastfeeding < 2 months, passive/active smoking, obesity, pets/molds exposure, high total serum immunoglobulin E (IgE), polysensitization (sensitized to 3 seasonal pollens with different structure), mixed sensitization (seasonal and perennial allergens), severe rhinitis (according to the Allergic Rhinitis and its Impact on Asthma guidelines), and lack of allergen-specific immunotherapy (SIT) for rhinitis preceding asthma diagnosis. Asthma phenotypes were characterized using the k-means clustering (silhouette method for cluster validation). Results: Asthma was diagnosed in 22 (66.7%) children and in 57 (69.5%) adults with SAR. Independent risk factors for asthma were lack of SIT preceding asthma diagnosis, both for children (P = 0.008132) and adults (P = 0.000017), and mixed sensitization for children (P = 0.035694). Asthma phenotypes identified in children according to the associated risk factors were: breastfeeding < 2 months and severe rhinitis in 16 (63.6%) patients; male, polysensitized, and severe rhinitis in 8 (36.4%) patients. Asthma phenotypes in adults were: polysensitization and severe rhinitis in 30 (52.6%) patients; male, exposure to pets, and severe rhinitis in 11 (19.3%) patients; and high total serum IgE and polysensitization in 16 (28.1%) patients. Conclusion: Lack of SIT is an independent risk factor for asthma both in children and adults with SAR, whereas polysensitization is a risk factor only for children. The dominant asthma phenotype in children with SAR is breastfeeding < 2 months and severe rhinitis. In adults with SAR, the dominant asthma phenotype is polysensitization and severe rhinitis.