The link between allergic rhinitis and chronic rhinosinusitis

Allergic rhinitis and chronic rhinosinusitis (CRS) are common disorders affecting millions of people worldwide. Although allergic rhinitis and CRS are distinct clinical entities, certain CRS endotypes share similar pathological mechanisms as those seen in patients with allergic rhinitis. This review assesses the literature behind the similarities and differences seen in patients with CRS and allergic rhinitis, and the role atopy might play in the pathophysiology of CRS.In examining the associations between allergic rhinitis and CRS, most studies have focused primarily on CRS with nasal polyps and type 2 inflammation in CRS. Recent studies have demonstrated the similarities and differences in pathologic mechanisms behind allergic rhinitis and CRS, with an emphasis on patient endotypes, genetics, and the nasoepithelial immunologic barrier. Related immunopathology shared by allergic rhinitis and type 2 inflammation in CRS has allowed for therapeutic overlap with biologic treatments.Allergic rhinitis and CRS often present as comorbid conditions, and understanding the relationship between allergic rhinitis and CRS is important when considering treatment options. Advances in understanding the genetics and immunology, as well as biologic and immunotherapeutic treatments have improved outcomes in patients with CRS, especially in the setting of atopy.