Publisher's Synopsis
Asthma is a chronic disease that affects your airways. It affects more than 20 million Americans. Asthma is characterized by inflammation and spasm of the airways. Your airways are tubes that carry air in and out of your lungs. If you have asthma, the inside walls of your airways become sore and swollen. That makes them very sensitive, and they may react strongly to things that you are allergic to or find irritating.Spasm (narrowing of the bronchial tubes) is caused by the inflammation of the muscles surrounding the air passageways. The inflammation makes the airways smaller makes it difficult to move air in and out of the lung. When your airways react, they narrow and your lungs get less air. This can cause wheezing, coughing, chest tightness and trouble breathing, especially early in the morning or at night.
