Defining and managing acute exacerbations of chronic rhinosinusitis

Currently, no universally accepted definition or management strategy for chronic rhinosinusitis (CRS) and its acute exacerbations (AECRS) exists. This review aims to provide an overview of the current research in this field and to present recent advances in diagnosis and management.

A variant in the CDHR3 gene has been identified as a risk factor for AECRS, associated with increased viral replication, type-2 cytokine upregulation, and downregulation of Toll-like receptor mediated responses. Microbiome studies show that patients with AECRS are more likely to harbor rare microbial taxa, and most strains isolated during exacerbations form biofilms. Biologic therapies targeting type-2 inflammation have reduced exacerbation rates and decreased the need for antibiotics and systemic corticosteroids. Culture-directed antibiotics may improve longer-term endoscopic outcomes, though short-term symptom and quality-of-life benefits remain unclear. Cost-effectiveness modeling suggests observation is usually the most efficient initial strategy, unless the probability of bacterial etiology exceeds ~49%. In addition, a new patient-informed definition of AECRS has been proposed, although further validation is needed.

Advances in genetics, microbiome analysis, and biologic therapy offer promising avenues, yet definitions and outcome measures remain inconsistent. Robust, long-term studies are still needed to harmonize definitions and standardize management.