Because of the common nature of asthma and the attention this disease has been given in recent years, it is important to consider the possibility of other disorders that may present in a similar manner to asthma. Failure to consider alternative diagnoses often leads to inappropriate treatment with medications such as systemic corticosteroids that result in untoward morbidity. This review will discuss several diseases originating not only in the tracheobronchial tree but also in extrapulmonary sites, such as the gastrointestinal tract, that may be mistakenly diagnosed as asthma. Newly described entities such as irritant vocal cord dysfunction and exercise-induced hyperventilation syndrome are discussed in this article, as is new information pertaining to well-established diseases such as Churg-Strauss syndrome and sarcoidosis.