Cough is one of the most important defensive reflexes. However,
extensive non- productive cough is a harmful mechanism leading
to the damage of human airways. Cough is initiated by activation
of vagal afferents in the airways. The site of their convergence is
particularly the nucleus of the solitary tract (nTS). The secondorder neurons terminate in the pons, medulla and spinal cord and
there is also the cortical and subcortical control of coughing. Upper
airway cough syndrome (UACS) – previously postnasal drip
syndrome - is one of the most common causes of chronic cough
together with asthma and gastroesophageal reflux. The main
mechanisms leading to cough in patients with nasal and sinus
diseases are postnasal drip, direct irritation of nasal mucosa,
inflammation in the lower airways, upper airway inflammation and
the cough reflex sensitization. The cough demonstrated by UACS
patients is probably due to hypersensitivity of the upper airways
sensory nerve or lower airways sensory nerve, or a combination of
both. Further studies are needed to clarify this mechanism.