Airway Inflammation: United Airway in Children

United airway disease (UAD) in children describes the shared epidemiologic, pathophysiologic, and clinical evidence that revealed the strong relationship among the most frequent and chronic inflammatory diseases of the upper and lower airways including allergic rhinitis (AR), chronic rhinosinusitis (CRS), and asthma (Table 33.1) [2, 4]. This concept proposes that these diseases are manifestations of a single unified airway inflammatory process and inflammation in one part of the airway will likely stimulate a similar reaction throughout the rest of the airway. Due to recent scientific improvements in the knowledge of mechanisms for chronic inflammation of both upper and lower airways, the concept of a single disease has been replaced by syndromes encompassing complex biological networks of distinct and interrelating inflammatory pathways (endotypes) with variable clinical presentations (phenotypes) [3].