Differential diagnosis of occupational asthma

Confidently establishing the diagnosis of occupational asthma (OA) is a complicated undertaking, because it requires that the patient's asthma symptoms are caused exclusively (or at least in large part) by occupational exposures. Asthma is a common disease, and the differential diagnosis of asthma is a frequently discussed subject that includes common and uncommon disorders. The differential diagnosis of OA includes these same disorders, plus several additional masqueraders that are relevant in the context of suspected occupational disease. This article presents a broad characterization of OA, including the elements necessary to establish a diagnosis. Differential diagnosis also is discussed.