Diseases that affect one portion of this epithelium, therefore, will commonly affect one or more other components. This model has been used to explain the strong overlap and comorbidities among diseases such as allergic rhinitis, chronic rhinosinusitis, and asthma. Since otolaryngologists commonly treat patients with rhinitis, rhinosinusitis, and laryngitis, a full exploration of the overlap among these diseases, as well as the importance of lower respiratory inflammation, is presented in this issue.