Upper Airway Cough Syndrome.

Upper airway cough syndrome (UACS), formerly known as postnasal drip syndrome, is one of the most common causes of chronic cough. It encompasses a spectrum of upper airway disorders, including allergic rhinitis, nonallergic rhinitis, and chronic rhinosinusitis which stimulate cough through mucosal inflammation and upper airway hypersensitivity. This article reviews the pathophysiology, diagnostic evaluation, and management of UACS from an otolaryngologic perspective. The lack of a clear diagnostic test requires clinical differentiation from other causes of chronic cough. Evidence-based treatment strategies aim to resolve cough through targeted control of airway inflammation and mucus production.