Asthma is a disease in your body's airways, which are the paths that carry air to your lungs. Asthma causes the inside walls of the airways to be inflamed or swollen. When this happens, people have repeated episodes of wheezing, breathlessness, chest tightness or nighttime or early morning coughing. Asthma is common among children and teens, but anyone can have asthma. Although there is no cure for asthma yet, asthma can be controlled when patients and doctors work together using medicines and management of environmental triggers.
You can also visit the U.S. Dept. of Health and Human Service's National Institute of Health, National Heart, Lung, and Blood Institute's asthma webpage.