Asthma is a chronic inflammatory disease of the airways that causes recurrent episodes of wheezing, breathlessness, chest tightness, and coughing, particularly at night or in the early morning.

These symptoms are often associated with widespread, but variable, airflow obstruction within the lung that is often reversible either spontaneously or with treatment.

The inflammation makes the airways hypersensitive to various triggers, leading to their constriction and increased mucus production in severe cases. This combination of airway narrowing along with excess mucus makes it harder for air to move in and out of the lungs, leading to the characteristic symptoms of an asthma attack.