Role of inflammation in non-allergic rhinitis

Objective: To investigate the role of inflammation in-non-allergic rhinitis (NAR) patients in a large series to establish the prevalence of different NAR-subtypes, clinical features and the role of nasal cytology in the diagnostic algorithm. Methodology: Patients were selected out of 3650 individuals who spontaneously presented at our institution. We consecutively enrolled 519 NAR-patients in an analytical cross-sectional study between November 2007 and June 2013 (level of evidence: 3b). All patients underwent rhinological evaluation including symptoms questionnaire, endoscopy, CT scan, allergy tests and nasal cytology. Results: The inflammatory cell infiltrate affects the severity of symptoms differently, allowing for identification of different phenotypes of NAR. We distinguished two groups:"NAR without inflammation"(NAR-) and "NAR with inflammation"(NAR+), in addition to different NAR-subtypes with inflammation. A significant difference was observed in terms of clinical symptoms and association with comorbidities (previously diagnosed asthma and aspirin intolerance) between NAR, NAR+ and between different NAR+ subtypes. Conclusion: Our data suggest that NAR- and NAR with neutrophils behave similarly, showing lower symptom score values and a lower risk of association with comorbidities compared to NAR with eosinophils and mast cells (singularly or mixed). In our belief it is very important to establish the presence and type of inflammation in non-allergic rhinitis patients and nasal cytology is a very useful test in correct differential diagnosis.