Asthma is a recurring health condition that affects your body's ability to move air in and out of your lungs. The condition affects about 15 million people in the United States -- nearly 5 million of them children. Asthma triggers are things that irritate the airways and cause them to narrow, such as pollen, smoke, or dust. These triggers can lead to an asthma attack, which includes symptoms such as wheezing and difficulty breathing. Anyone with possible asthma symptoms should see a doctor to develop an appropriate treatment plan and learn how to avoid potential asthma triggers. While asthma cannot be cured, for most patients it can be controlled -- allowing people with asthma to live an active life with only minimal and infrequent symptoms.