Oxidative Stress in Chronic Rhinosinusitis with Nasal Polyps: Pathophysiological Mechanisms, Biomarkers, and Therapeutic Implications

Background and Objectives: Chronic rhinosinusitis with nasal polyps (CRSwNP) is a heterogeneous inflammatory disease of the sinonasal mucosa characterized by persistent symptoms, high recurrence rates, and a significant impact on quality of life. Increasing evidence suggests that oxidative stress plays a role in its pathophysiology, although its precise contribution remains incompletely defined. Materials and Methods: A narrative review was conducted following SANRA recommendations. A structured literature search was performed using PubMed, Scopus, and Google Scholar to identify studies investigating oxidative stress, antioxidant systems, and molecular pathways in CRSwNP. Relevant articles published between January 2000 and March 2026 were included and critically appraised, distinguishing clinical from ex vivo, in vitro, and animal evidence.