What is asthma?
Asthma is a serious, sometimes life-threatening respiratory disease that affects the lungs and the quality of life for millions of Americans.  Asthma affects people of all ages, but frequently begins in childhood. More than 22 million Americans are known to have asthma; 6 million people diagnosed with asthma are children.

Asthma is a chronic respiratory disease that affects the airways, or tubes, that carry air in and out of your lungs.  Particularly, asthma affects the inside walls of your airways and they become sore and swollen. As the airways swell, they may react strongly to things that you are allergic to or find irritating. When your airways react, they get narrow and your lungs get less air causing repeated episodes of wheezing, breathlessness, chest tightness, and night or early morning coughing.

Do doctors know what causes asthma?  And can you avoid certain risk factors to prevent the development of asthma?  more here on the risk factors and causes of asthma in the next section on what causes asthma.