- Background: Chronic rhinitis (CR) is characteristically divided into several major clinical phenotypes: allergic rhinitis (AR); nonallergic, noninfectious rhinopathy (NAR); and chronic rhinosinusitis (CRS). CRS has two phenotypic variants: CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). An area of growing interest is to identify biologic markers that could assess different aspects of CR phenotypes. Objective: The aim of the study was to evaluate four CR biomarkers: endothelin-1 (ET-1), thymus and activation-regulated chemokine (CCL17), neopterin, and α-defensins in subjects with AR, NAR, and CRS. Methods: Fifty-one patients with AR, 43 patients with NAR, 46 patients with CRSsNP, 54 patients with CRSwNP, and 40 healthy controls were included. ET-1, TARC/CCL17, neopterin, and α-defensins levels in subjects' serum and nasal secretions (NS) were measured by the enzyme-linked immunosorbent assay. Results: High NS levels of ET-1, TARC/CCL17, and α-defensins were characteristic for CRSwNP, although only high NS levels of neopterin were found in the CRSsNP phenotype. AR phenotype was characterized by high NS levels of ET-1 and TARC/CCL17. In the subjects with NAR, none of these biomarker levels in serum and NS differed from those of healthy controls. Conclusions: CR can be categorized by ET-1, TARC/CCL17, neopterin, and α-defensins into several disease phenotypes. Further studies are needed to better investigate pathophysiologic roles of these biomarkers in CRS.