Development of allergic rhinitis in early life: A prospective cohort study in high-risk infants

Background Allergic rhinitis (AR) is the most common allergic disease in children. The development process of AR in early childhood, however, is not well understood. We prospectively investigated the process in regard to not only the nasal symptoms and sensitization but also the nasal cytology, in relation to recurrent wheeze in a high-risk cohort. Methods Infants under 2 years of age with atopic dermatitis (AD) and/or food allergy (FA) symptoms were recruited and followed prospectively for 2 years. The phenotype of perennial AR was classified based on the presence/absence of (1) persistent nasal symptoms, (2) nasal eosinophils, and (3) HDM sensitization, the most common allergen for perennial AR in Japan. AR-like phenotypes were defined as positive for at least two of those three categories. High-risk recurrent wheezer was diagnosed based on the Japanese guidelines and Global Initiative for Asthma. Cox proportional hazards regression analyses for high-risk recurrent wheeze and the AR-like phenotype, adjusting for known covariate risk factors for asthma. Results A total of 299 children were enrolled, and 237 subjects (78%) completed the 2-year observation. The prevalence of eosinophilia in nasal secretions increased from 18.5% to 69.9%, while HDM-specific IgE >= 0.35 kU(A)/L increased from 30.6% to 74.8%. AR-like phenotypes increased from 18.4% to 65.0%. The AR-like phenotype at 2 years was associated with development of high-risk recurrent wheezer (HR 2.062; 95% CI 1.005-4.796). Conclusions The prevalence of an HDM-related AR-like phenotype was markedly increased during infancy in infants with AD/FA and was associated with high-risk recurrent wheezer.