ABSTRACT
It has long been recognized that respiratory infections are closely associated with exacerbations of asthma (1). Patients that present to the ED with acute exacerbations of asthma often give a history of antecedent cold symptoms, which has lead many investigators to try to determine a causal link between acute respiratory infections and the development of acute symptoms of asthma (2,3,4). The etiology of acute respiratory infections may be either viral or bacterial, and range from a simple ‘‘cold’’ to a consolidated lower airway pneumonic process. Viral respiratory infections have been shown to be far more important in provoking exacerbations of asthma than bacterial infections. In the pediatric population, viral infections are the most important trigger for acute asthma, and although studies have shown conflicting results, this is likely to be true for adults as well (5). This chapter will review the historical and epidemiological data that have established viral infections as a leading precipitant of acute asthma attacks and will discuss mechanisms and theories for viral provocation of attacks.
