Exacerbations of asthma and COPD: definitions, clinical manifestations and epidemiology.

Exacerbations are important events in patients with asthma and chronic obstructive pulmonary disease (COPD). Reducing the number, frequency and the severity of exacerbations is therefore an important management goal identified by treatment guidelines for both diseases. There are similarities with respect to clinical manifestations, etiology and epidemiology, but there are also clear differences not the least in how well patients respond to treatment. The similarities and differences between exacerbations asthma and COPD with an emphasis on epidemiology and clinical presentation are discussed and compared in this chapter.