Exacerbations of sarcoidosis are common. In particular, exacerbations of pulmonary sarcoidosis are reported in more than one-third of patients. Despite their frequent occurrence, there is little medical evidence concerning the definition, diagnosis, and treatment of pulmonary exacerbations of sarcoidosis. In this article, we propose a definition of acute pulmonary exacerbations of sarcoidosis (APES). We review the meager medical literature concerning the risk factors, diagnosis, and treatment of this condition. Given the limited information concerning APES, we acknowledge that this article is not a definitive resource but, rather, a position paper that will encourage greater consideration of the pathogenesis, diagnostic challenges, and treatment approaches to this condition. We believe that further focus on APES will improve the quality of care of patients with pulmonary sarcoidosis. CHEST 2012; 142(4):827-836