Upper Airway Cough Syndrome (UACS) is a group of chronic coughs with symptoms of the upper airway from the back of the nose to the throat, with abnormal sensations arising from the pharynx, most commonly the sensation of a posterior nasal discharge.
This condition is very common in adults with chronic cough lasting more than eight weeks.
A persistent dry (less expectorant) cough lasting at least eight weeks with a sensation of something stuck in the pharynx, especially the presence of mucus in the pharynx, is considered to be UACS.
UACS was previously known as posterior rhinorrhoea syndrome. However, it is unclear whether the mechanism of the cough is due to discharge of secretions from the nose or sinuses into the pharynx or to direct inflammation/stimulation of cough receptors in the upper respiratory tract. In addition, the sensation referred to as posterior rhinorrhoea may actually be a manifestation of a sensory neuropathic process and may not be related to the rate or volume of nasal discharge. Expert opinion is moving towards the view that many of the features of UACS are part of the general ‘cough hypersensitivity syndrome’, and furthermore, some researchers object to the existence of the disease category UACS itself as a single clinical entity. For these reasons, the post-rhinorrhoeic symptoms associated with chronic cough are now commonly viewed as a condition called UACS, and the fiction that a dripping nose causes a cough is a thing of the past.
While attempts at empiric treatment with antihistamines and hyperemia removers are not futile from a therapeutic point of view, treatment for cough from the lower respiratory tract alone can partly help to reduce upper respiratory tract symptoms.