Central Compartment Atopic Disease Within the Chronic Upper Airway Inflammatory Continuum: A Scoping Review of Sinonasal Compartmentalization and Type-2 Airway Disease.

PURPOSE OF REVIEW: To map evidence supporting a chronic upper airway inflammatory continuum (CUAIC) linking localized allergic inflammation, central compartment atopic disease (CCAD), diffuse type 2 chronic rhinosinusitis (CRS), and broader T2-airway disease. RECENT FINDINGS: A scoping review of five databases identified 58 studies from January 2014 to April 2026. Evidence described a non-linear spectrum extending from local allergic rhinitis and localized sinonasal responses to CCAD, diffuse CRSwNP, and lower-airway comorbidity. Endoscopy provided the clearest anatomical anchor, with CCAD representing a recognizable central-compartment phenotype. Radiological findings ranged from limited central changes to multi-sinus opacification, while biomarkers suggested enrichment from local allergic markers to tissue eosinophilia, type 2 cytokine activity, and lower-airway traits. The CUAIC conceptualizes CCAD as an intermediate or overlapping phenotype between localized sinonasal allergy and broader type 2 airway disease. It reflects persistence, overlap, or expansion rather than an obligatory sequence. Prospective longitudinal studies are needed to validate its clinical utility.