Correlation of Nasal Eosinophilia and Response after Nasal Provocation Test in Patients with Nonallergic Rhinitis

Objectives We aimed to evaluate the relationship between nasal eosinophilia and nasal hyperresponsiveness to allergen extract. Study Design Retrospective chart review. Setting Academic tertiary rhinologic practice. Subjects and Methods We performed allergy tests (skin prick test and multiple allergosorbent test) and nasal cytology for 194 patients with rhinitis symptoms (76 males and 118 females; age, 11-69 years). According to the results, they were classified into 4 groups: group A (allergic rhinitis with eosinophilia, n = 26), group B (allergic rhinitis without eosinophilia, n = 77), group C (nonallergic rhinitis with eosinophilia syndrome, n = 20), and group D (nonallergic rhinitis without eosinophilia, n = 71). We performed a nasal provocation test (NPT) using house dust mite extract and assessed the changes in symptoms and the decrease in acoustic parameters (total nasal volume and minimal cross-sectional area [MCA]). Results Patients in group C were more likely to have severe rhinorrhea and sneezing than those in group D ( P < .001). After NPT, group C had greater aggravation of nasal obstruction than group D ( P < .001). Group C also showed markedly greater MCA changes as compared with group D 15 minutes after the antigen challenge ( P = .002). There was significant correlation between the number of eosinophils and an increase in nasal obstruction ( r = 0.319, P = .0009), rhinorrhea ( r = 0.302, P = .0017), sneezing ( r = 0.219, P = .0241), change in the total nasal volume 15 minutes after NPT ( r = 0.287, P = .0028), and change in the MCA 15 minutes ( r = 0.322, P = .0008) and 30 minutes ( r = 0.250, P = .0098) after NPT. Conclusion In patients with NAR, nasal eosinophilia is associated with provocative response after NPT. Further research should be performed to elucidate the mechanisms that underlie this phenomenon.