Main Findings from Retrospective Studies on the Comorbidity of Asthma and Sinusitis and Their Implications for Clinical Practice

Asthma and chronic rhinosinusitis (CRS) are prevalent chronic inflammatory conditions of the airways that frequently occur together, contributing to increased disease burden and reduced quality of life. This study aimed to synthesize findings from retrospective research to better understand the clinical and pathophysiological interrelations between these two conditions. A narrative review was conducted, including studies (2002–2025) assessing prevalence, lung function, biomarkers, quality of life, and treatment outcomes in patients with confirmed asthma and/or CRS. The results revealed a high prevalence of comorbidity, particularly in patients with CRS with nasal polyps (CRSwNP), where asthma co-occurrence exceeds 50% in certain phenotypes. Shared type 2 inflammatory mechanisms, including eosinophilic infiltration, cytokine overexpression (IL-4, IL-5, and IL-13), and tissue remodeling via matrix metalloproteinases, were frequently identified. These findings support the unified airway model and highlight the systemic nature of inflammation in these patients. Biologic therapies demonstrated effectiveness in reducing exacerbations and improving clinical outcomes, especially in patients with more severe phenotypes. The inclusion of dentistry and oral health as components of the systemic inflammatory burden offers an innovative perspective and reinforces the importance of holistic, interdisciplinary care. This study underscores the need for a multidisciplinary, phenotypically guided approach to treatment. Recognizing and systematically addressing this comorbidity can improve disease control and enhance patient quality of life.