Mechanistic and Clinical Updates in Chronic Rhinosinusitis: 2023-2025.

Chronic rhinosinusitis (CRS) is a chronic inflammatory condition of the nose and paranasal sinuses associated with poor quality of life and high health care burden. CRS is broadly classified into two subtypes based on whether nasal polyps are present (CRSwNP) or absent (CRSsNP). While CRSsNP is more prevalent, the underlying mechanisms contributing to CRSwNP pathogenesis have been more extensively defined over the years. CRSwNP is characterized by type 2 (T2) inflammation as well as epithelial barrier dysfunction and in the past 3 years, a new endotype has been defined, inflammatory cell heterogeneity has been identified, novel cell populations have been discovered, and mechanisms contributing to epithelial barrier dysfunction have been advanced. Clinically, 4 biologics targeting T2 inflammation are now approved for CRSwNP. As these therapies become increasingly common in clinical practice, ongoing investigations have focused on comparing their efficacy and defining their role alongside more established interventions such as corticosteroids and sinus surgery. In this review, novel mechanistic findings and recent clinical developments in CRS between 2023 and 2025 will be highlighted.