Oxidative stress: a pivotal regulator of inflammation and endotypes in Chronic rhinosinusitis

INTRODUCTION: Chronic rhinosinusitis (CRS) is a heterogeneous inflammatory disease with distinct immune endotypes and variable clinical outcomes. Oxidative stress contributes to this heterogeneity by linking epithelial injury, persistent inflammation, and tissue remodeling. AREAS COVERED: PubMed was searched for relevant studies published between January 2016 and December 2025. Earlier seminal studies were included when appropriate. Excess reactive oxygen species (ROS) and impaired antioxidant defenses disrupt mucosal redox balance and sustain inflammation. Eosinophils and neutrophils contribute through distinct but overlapping oxidative mechanisms. Their coexistence may intensify inflammation in mixed endotypes. Redox alterations may aid endotype classification, prognosis, and treatment assessment. Antioxidants and other redox-targeted approaches have shown promise in experimental models. EXPERT OPINION: Clinical evidence for redox-targeted treatment remains limited. Defining endotype-specific redox profiles may improve disease stratification and clarify whether restoring redox balance improves clinical outcomes.