Allergen sensitization patterns: Allergic rhinitis with multimorbidity versus alone-A real-world study

Background: Allergic rhinitis (AR) multimorbidity may need to be considered a specific disease because of distinct clinical and immunological differences from AR alone. Allergic multimorbidity often involves polysensitization, where allergen-specific immunoglobulin E (IgE) plays a significant role. Objective: This study aims to explore differences in allergen IgE sensitization patterns between AR alone and AR multimorbidity. Methods: A real-world case-control study was conducted with patients diagnosed with AR. Multivariate logistic regression analyzed the associations between AR multimorbidity and allergen sensitivity, allergen-specific IgE levels, and the count of positive allergens. Results: A cohort of 2275 patients with AR was included, of which 1100 (48.4%) presented with AR alone, while 1175 (51.6%) exhibited AR multimorbidity. Patients with AR multimorbidity had a more diverse allergen profile than those with AR alone. An increased number of positive ingested allergens had a higher odds ratio (OR) for AR multimorbidity compared with inhaled allergens (1.46 vs. 1.96) across all phenotypes. Sensitization to allergens and their allergen-specific IgE levels, including dust mites, cat dander, and milk (p < 0.05), were associated with AR multimorbidity. In children, cat and dog dander were significant allergens associated with AR multimorbidity (p < 0.05). Conclusions: Allergen sensitization patterns in AR multimorbidity differ from those in AR alone. Polysensitization, particularly to ingested allergens, increases the risk of allergic multimorbidity. The risk of allergic multimorbidity also increases with specific allergen positivity and higher allergen-specific IgE levels.