Relationship between nonallergic upper airway disease and asthma.

A growing body of scientific evidence supports the link between nonallergic upper airway disorders and asthma. Multiple studies have demonstrated that most patients with nonallergic asthma have chronic nasal symptoms as well as radiographic evidence of sinus mucosal disease. Equally important, preexisting symptoms of rhinitis place nonallergic patients at higher risk for developing asthma. Experimental studies demonstrate that the upper and lower airways may be connected via a number of paths, and that the systemic circulation may play a key role in amplifying inflammation in other portions of the respiratory tract. Finally, given this complex relationship between localized and systemic inflammation, it behooves all physicians to assess and treat rhinitis and sinusitis when they are present in patients with asthma.