Differential diagnosis of asthma and chronic obstructive pulmonary disease (COPD) is based on a combination of the patient’s medical history, physical examination findings, and confirmation of the presence of reversible or irreversible airflow obstruction using spirometry. Differentiating between asthma and COPD is essential for determining the appropriate drug therapy. Inhaled corticosteroids are the most effective medications currently available for the control of asthma. However, the basis for treatment in COPD is an inhaled, long-acting bronchodilator. Taking all of this into account, it is important to increase awareness of the differences between the two diseases to promote optimal treatment.
A further difficulty in the management of obstructive lung diseases is that in some individuals, there may be characteristics of both asthma and COPD. These may be patients with asthma who started to smoke and developed chronic airflow obstruction with a high degree of reversibility or heavy smokers with a genetic background that leads to the production of an eosinophilic response to inhaled particles and results in clinical features similar to those of chronic asthma. These patients are usually excluded from clinical trials of asthma treatments because they smoke and are excluded from trials of COPD because they either have a history of asthma or show great airflow reversibility. This review is dedicated to the analysis of the characteristics and treatment of this particular group of patients with obstructive lung disease, which has been described as the “overlap” phenotype between
asthma and COPD.