The aim of this review is to assist pulmonologists in the management of diseases involving both the upper and lower respiratory tract that are linked by a common, interrelated epidemiology, clinical signs and symptoms, and inflammatory mechanism - asthma, in particular. The document discusses the definitions of the various sinonasal phenotypes associated with asthma: allergic and non-allergic rhinitis and chronic rhinosinusitis with or without nasal polyps. Diagnostic criteria and severity levels are also listed. Particular attention has been given to the 2 main syndromes associated with asthma: (i)allergic rhinitis, the most common, and (ii)chronic rhinosinusitis with nasal polyps, the disease most closely associated with severe asthma. To summarize, the upper respiratory tract should always be evaluated in order to achieve a single diagnosis and comprehensive treatment of the "united airway".