Variability of Diagnostic Outcomes in Nasal Allergen Challenge: The Role of Combined Subjective and Objective Indicators.

BACKGROUND: Nasal allergen challenge (NAC) is currently the only available test to confirm nasal responsiveness to allergens and is a core diagnostic tool for allergic rhinitis. NAC is currently diagnosed by combining existing subjective measures and objective assessment methods in pairs to assess outcomes, based on a strong positive result for a single item or a moderately positive result for a combination of two items. However, there are few data on the diagnostic outcomes and characteristics of its various diagnostic combinations. OBJECTIVE: To evaluate the differences and characteristics of various existing diagnostic methods (combinations of subjective and objective indicators) for NAC. METHOD: During January 2023-December 2024, patients with history of chronic rhinitis (CR) who experienced nasal symptoms upon exposure to dust, as well as healthy controls, were enrolled. Demographic and clinical data were collected, followed by a NAC with Dermatophagoides farinae (Df). Total nasal symptom score (TNSS), visual analog scales (VAS), acoustic rhinometry (AcRh), Active anterior rhinomanometry (AAR) and 4-phase-rhinomanometry (4PR) were used for assessment before and after NAC. The diagnostic results, minimum NAC concentration at positive trigger, and type of positive response (subjective or objective) were recorded. RESULT: A total of 180 patients and 133 healthy controls were enrolled in the study. Significant differences in positive rates were observed across the six diagnostic evaluation combinations (p = 0.001). The combination of subjective TNSS evaluation with objective AAR assessment demonstrated the highest positive rate among patients (55.6%), whereas the combination of subjective VAS evaluation with objective AcRh assessment yielded the lowest positive rate (31.7%). Furthermore, when diagnostic combinations triggered positive results, they favored strong objective positivity. CONCLUSION: The diagnostic results derived from pairwise combinations of various subjective measurements and objective assessments exhibit variability, with objective assessments demonstrating a higher propensity to yield positive results compared to subjective measurements.