Evaluation of wheezing in the nonasthmatic patient.

Wheezing is a nonspecific manifestation of airway obstruction. Even though bronchial asthma is the most common cause of wheezing, a variety of pulmonary and nonpulmonary conditions can present with this symptom. In recent years methacholine provocation challenge has simplified detection of bronchial asthma; however, establishing accurate diagnosis of other causes of wheezing is important because each condition requires specific treatment. This article describes a methodical approach to the diagnosis of wheezing in patients who are not asthmatic.