Allergic Disease Phenotypes and Their Clinical Correlates: A Real-World Observational Analysis

Abstract

Background: Allergic diseases present with diverse clinical phenotypes and variable treatment outcomes. Understanding the relationship between these phenotypes and clinical responses to allergen immunotherapy (AIT) in real-world settings is critical for optimizing care and improving adherence. Objective: This study aimed to evaluate the clinical and demographic characteristics associated with treatment outcomes in patients undergoing AIT and to explore the relationship between allergic disease phenotypes and adherence in routine practice. Methods: In this an observational cross-sectional study, we analyzed data from 109 patients treated with AIT between 2020 and 2022 at a tertiary allergy center. Patients were grouped based on clinical outcome into "improved" or "discontinued." Variables assessed included sex, year of treatment initiation, number and type of allergic diseases, and presence of multiple allergy phenotypes. Associations were tested using Chi-square statistics, with p < 0.05 considered significant. Results: Of the 109 patients, 66 (60.6%) reported clinical improvement, while 37 (33.9%) discontinued therapy. The most frequent phenotypes were allergic rhinitis (52.3%), urticaria (50.5%), and bronchial asthma (47.7%). Improvement rates were highest among patients with allergic rhinitis (71.9%), asthma (71.2%), and those with four or more coexisting allergies (85.7%), although differences were not statistically significant. Patients with “other allergies” (e.g., drug, insect, or contact allergies) showed less favorable trends, possibly reflecting heterogeneous presentations and unmet diagnostic needs. No significant associations were observed for sex or year of initiation. Conclusion: This analysis highlights that clinical improvement in AIT is more strongly associated with adherence and complexity of allergic phenotypes than with demographic factors. Patients with multiple allergic conditions may achieve better outcomes due to increased engagement with care. These findings underscore the need for standardized adherence measures and phenotype-specific management strategies in allergy clinics.