Chronic cough in childhood: approach to diagnosis and treatment.

Chronic cough in childhood has many possible causes. The two most common are asthma and viral upper respiratory infection. Although usually associated with wheezing, dyspnea, or both, cough may be the sole manifestation of asthma ("cough-variant asthma"). Most important to initial evaluation are physical examination, patient history, and chest radiograph. Bronchial provocation testing may also prove helpful but is usually unnecessary. A trial of antiasthma therapy is appropriate when the pattern of symptoms is typical of asthma (excepting the lack of wheezing) and when nothing incompatible with asthma is present in the clinical picture. Drug therapy for cough-variant asthma is the same as that for more typical asthma. A vigorous trial of antiasthma therapy should not be considered complete unless a short course of high oral doses of corticosteroids has been included. The presence of clinical signs or symptoms atypical or incompatible with asthma and the failure of symptoms to respond to aggressive antiasthma therapy both warrant a more aggressive and complete diagnostic study.