Cough is an important medical and economic problem. It is a common symptom of a number of respiratory and nonrespiratory disorders. It has a substantial impact on health; it represents the most common symptom leading patients to consult with their doctor.1
Traditionally, cough has been categorized as follows based on duration: acute cough, lasting < 3 weeks; subacute cough, lasting 3 to 8 weeks; and chronic cough, lasting > 8 weeks.2– Most of the published studies on cough have concentrated on chronic cough. In this issue of CHEST (see page 1142), Kwon et al3 make an important contribution and fill a void in the literature by prospectively looking at the causes of subacute cough. They report on 529 patients with a complaint of cough from Seoul, Korea, but focus on the 184 patients who met the criteria for subacute cough. Their initial approach included obtaining a medical history, and performing a physical examination, pulmonary function studies, including a methacholine bronchoprovocation challenge (BPC), chest roentgenogram, and an induced sputum test measuring eosinophils. No initial therapy was given. Patients were seen 7 to 10 days later. Cough had spontaneously resolved in 62 of 182 patients (34%). A diagnosis of “postinfectious cough,” based on predefined criteria, was given to most patients with spontaneously resolving cough (74.3%).