Cough in Asthma Is due to Eosinophilic Airway Inflammation: A Pro/Con Debate
Multiple prospective studies have demonstrated that asthma is among the most common etiologies of chronic cough, along with upper-airway cough syndrome (formerly known as postnasal drip syndrome) and gastroesophageal reflux disease. More recently, the entity of nonasthmatic eosinophilic bronchitis has been appreciated as a significant cause of chronic cough worldwide. Chronic cough associated with both of these conditions typically responds well to therapy with systemic or inhaled corticosteroids, thus leading to a general assumption that the suppression of eosinophilic airway inflammation explains the improvement in cough. However, some recent studies challenge a causal relationship between eosinophilic airway inflammation and cough in asthmatics. The 4th American Cough Conference, held in New York in June 2013, provided an ideal forum for discussion and debate of this issue between two internationally recognized experts in the field of asthma and chronic cough.