Asthma

Asthma is a disease in which inflammation of the airways causes the restriction of airflow into and out of the lungs. The muscles of the bronchial tree become tight and the lining of the air passages swells, reducing airflow and producing the characteristic wheezing sound. This is known as an asthma attack. These attacks can occur as a reaction to an allergen or other substance (acute asthma), or as a part of a complex disease cycle, which may include reaction to stress or exercise (chronic asthma).