Cellular and immune mechanisms of acute exacerbations of chronic rhinosinusitis

Acute exacerbations of chronic rhinosinusitis (AECRS) represent an important and distinct phenotype of chronic rhinosinusitis (CRS) about which much remains to be learned. The widely adopted definition of AECRS consists of a flare-up of distinctly worsened symptoms lasting 3 days or more from a chronic inflammatory baseline, which prompts an escalation of treatment. Patients with worse baseline CRS symptomatology have been shown to experience more frequent AECRS episodes. In addition, characteristics of patients who experience more frequent AECRS episodes include comorbid asthma, a high body mass index, and longer-term CRS status. As both asthma and AECRS are type 2 inflammatory responses, many parallels can be drawn between the 2 airway diseases to help elucidate the pathophysiologic mechanism driving AECRS. Thus far, the mainstay of treatment has been oral antibiotics and systemic corticosteroids; however, several biological therapies have shown promising efficacy in reducing AECRS frequency through their ability to control baseline CRS inflammation. Novel studies can focus on measuring the effect of specific interventions on AECRS frequency to better delineate the full efficacy of the drug in question.