By: National Institute of Environmental Health Services
Asthma is an inflammatory disease of the lung. This inflammatory process can occur along the entire airway from the nose to the lung. Once the airway becomes swollen and inflamed, it becomes narrower, and less air gets through to the lung tissue. This causes symptoms like wheezing, coughing, chest tightness, and trouble breathing. During an asthma attack, the muscles around the airways tighten up and the asthma symptoms become even worse than usual.
Once considered a minor ailment, asthma is now the most common chronic disorder in childhood. The prevalence of asthma has progressively increased over the past 15 years. In the United States alone, nearly 40 million people — 13.3 percent of adults and 13.8 percent of children — have been diagnosed with asthma.
