Differential diagnosis of adult asthma.

Although the term "all that wheezes is not asthma" is not new, and the long list of asthma masqueraders has remained essentially the same for several decades, the importance of knowing when to question the accuracy ofa diagnosis of asthma has remained critical for physicians who care for patients with respiratory symptoms. The concepts of "asthma control" and"asthma severity" are currently evolving, although the fundamental hall-marks that define the syndrome of asthma endure and should be mastered by asthma specialists. Asthma masqueraders, including several that may confound a correct diagnosis of asthma, are important to consider when either the presentation of asthma is atypical or the response of the patient to treatment is suboptimal. COPD and VCD head the list of diagnoses most likely to be confused with asthma in everyday practice. Correctly identifying the diagnosis of COPD enables implementation of an up-to-date treatment plan that differs from asthma management. VCD is a vastly under recognized syndrome whose existence is widely accepted but whose pathophysiology is poorly understood, and correctly identifying a VCD component to asthma symptoms enables both a reduction in costly and potentially harmful asthma medications and focus on specific VCD treatment, such as speech therapy. For less common and uncommon asthma masqueraders, it is important to be familiar with their typical clinical presentation and basic diagnostic approaches.