Cough variant asthma: usefulness of a diagnostic-therapeutic trial with prednisone.

Cough variant asthma is characterized as a persistent, nonproductive cough with minimal or no wheezing and dyspnea. The diagnosis can be overlooked or misdisagnosed. We describe the severity of cough, the misery of some patients who have this syndrome and the usefulness of a diagnostic-therapeutic trial in ten patients with cough variant asthma. We evaluated ten patients whose chief complaint was persistent nonproductive cough. During the course of evaluation, all patients received a diagnostic-therapeutic trial of prednisone for cough variant asthma after other major causes of cough had been excluded. The duration of cough ranged from 2 months to 20 years. Some patients had significant side effects from coughing including interference with social life, work and sleep, urinary incontinence, stool incontinence, hoarseness, and vomiting. After a diagnostic-therapeutic trial with prednisone, nine patients reported significant improvement of cough in three days. One patient required 2 weeks of therapy for optimal improvement. All were subsequently controlled primarily with inhaled conticosteroids. The diagnosis of cough variant asthma may not be made for a prolonged time. A short course of prednisone as a diagnostic-therapeutic trial can establish a diagnosis and be followed by an effective method of control of cough by inhaled corticosteroids.