Asthma is a long-term (chronic) disease of the respiratory system that causes inflammation and spasm or tightening in the bronchial tubes, which carry air to the lungs. The inflammation causes periodic episodes of difficulty breathing, wheezing, chest tightness, and coughing.

Although asthma cannot be cured, most people can control their asthma by following a plan, avoiding triggers, and taking medicine.

Asthma often begins during childhood and may last throughout a person's life.

The cause of asthma is not clearly known. It is more common in people who also have allergies.