Asthma is a chronic lung condition affecting about 20 million people in the U.S. People with asthma have very sensitive airways and certain triggers cause the airways to become inflamed and swollen. This inflammation can lead to coughing, wheezing and other breathing difficulty. Asthma symptoms can range from a mild nuisance to life-threatening emergencies. There is no cure for asthma, but medication and other treatments can help keep symptoms under control.