Asthma

Asthma is a disease in which inflammation of the airways restricts airflow in and out of the lungs. The word asthma comes from the Greek word for "panting." The panting and wheezing sound characteristic of asthma occur because of the restricted flow of air.

Normally, when you breathe in an irritant or are subjected to a stressor such as exercise, your airways relax and open, allowing the lungs to get rid of irritants or take in more air. In a person with asthma, muscles in the airways tighten and the lining of the air passages swells. The immune system gets involved, but instead of helping, it causes inflammation.

Asthma is a disease of both adults and children. In fact, asthma is the most common chronic childhood illness. About half of all cases of asthma develop before the age of 10. Many children with asthma also have allergies. While there is no cure for asthma, it can be controlled.