[Eosinophilic airway disorders: important causes of prolonged cough in Japan].

We studied 223 outpatients who presented between October 2001 and June 2003 with persistent cough of more than 3 weeks' duration. Eosinophilic airway disorders (EAD), including atopic cough and cough variant asthma, were clinically diagnosed in 119 patients, on the basis of the following factors: history of atopic disease, duration of cough, history of previous prolonged cough, or presence of forced expiration wheeze. Since eosinophils are frequently found in the sputum of patients with EAD, a positive test strongly suggests the presence of EAD.