Unified Airway Disease: A Contemporary Review and Introduction.

Upper and lower airways diseases are very common, with population prevalence of 10% to 40%. The conditions are usually interlinked and referred to as "unified airway disease" or "the united airways." Especially in phenotypes with more severe disease, type 2 immunologic endotype is often noted. Comorbid upper and lower airway diseases are usually caused by similar underlying immunologic response. Any patient with rhinitis or rhinosinusitis should have their lower respiratory tract evaluated. A multidisciplinary approach in the diagnosis and treatment of airway disease is advised, especially, for more severe phenotypes.