Acute asthma presentations account for 2 million emergency department visits annually in the United States. The causes for these presentations range from undertreated or unrecognized disease, to exacerbations of stable disease usually caused by recent exposure to triggers of exacerbations, to severe disease states unresponsive to conventional therapy. Indeed, many of these patients often exhibit both acute and chronic markers of severe asthma. The recognition of these phenotypes of acute asthma can enhance the management of these patients in acute and emergency settings. This article describes these potential phenotypes, reviews current therapies, and addresses the challenges of variability of therapeutic response in acute asthma.