Nasal obstruction is the key symptom in hay fever patients.

Allergic rhinitis is characterized by a Th2-dependent inflammation. Nasal obstruction largely depends on allergic inflammation.The aim of this study was to evaluate the possible role of the symptom nasal obstruction in assessing patients with hay fever.Fifty patients (mean age, 23.7 +/- 4.9 years) with hay fever were evaluated both during and outside pollen season. All of them had moderate-severe grade of nasal obstruction. Total symptom score (TSS), rhinomanometry, nasal lavage, nasal scraping, spirometry, and methacholine bronchial challenge were performed in all subjects.During the pollen season, patients with severe nasal obstruction showed significantly higher values of TSS, IL-4, IL-5, IL-8, nasal eosinophils and neutrophils, and significantly lower values of nasal airflow, IFNgamma, FEV1, FVC, and FEF 25-75 in comparison with patients with moderate nasal obstruction. Twenty (83\%) patients with severe nasal obstruction showed bronchial hyperreactivity (BHR), whereas only 6 (25\%) patients with moderate nasal obstruction had BHR. Outside the pollen season overlapping results were observed.This study provides evidence about the key role played by nasal obstruction in assessing patients with allergic rhinitis