While the increase in the prevalence of asthma has abated, levels of asthma morbidity and mortality remain near record highs. An asthma exacerbation is a major factor contributing to morbidity, and even mortality in patients with asthma. Although current approaches to treatment have reduced these risks, asthma exacerbations are major problems for inner-city patients and their families, and prevention of these events continues to be a significant challenge. In children with asthma, there are predictable seasonal epidemics of exacerbations, especially during the fall season, otherwise known as the "September epidemic."