Obstructive lung disorder (OLD) is an umbrella term for lung disorders that are characterized by a limitation of airflow. The two most common kinds of OLDs are chronic obstructive pulmonary disease (COPD) and asthma, but bronchiectasis and cystic fibrosis are also OLDs.
In asthma, the airways are obstructed when they become inflamed, usually in response to a trigger. This inflammation and resulting obstruction of the airways is reversible. These triggers may include dust, cats, pollen from trees and plants, or cigarette smoke. In COPD, the obstruction of the airways can be caused by inflammation of airways, emphysema, or an excess of mucus. The airway obstruction associated with COPD is generally not fully reversible.