Asthma is a chronic disease that affects the airways. Airways are tubes that carry air in and out of the lungs. Asthma causes the inside walls of the airways to become sore and swollen, which makes them very sensitive and may cause a strong reaction to allergens or irritants. When airways react to allergens or irritants, they get narrower and cause the lungs to get less air. This can cause wheezing, coughing, chest tightness and trouble breathing, especially early in the morning or at night.

Asthma is commonly seen in children. It is a leading cause of hospital admissions and school absences. Children with asthma may be able to breathe normally most of the time; however an asthma attack can occur when children encounter a substance (a trigger) that can cause problems. Common asthma triggers include:

• Tobacco smoke

• Dust, pollen, mold

• Exercise

• Viral infections, such as the common cold

• Animals (hair or dander)

• Chemicals in the air or in food

• Changes in weather (most often cold weather)

• Strong emotions

• Aspirin and other medications

The pediatric asthma inpatient volume measure is reporting on the total number of admissions to a hospital for asthma-related illnesses.