Asthma
More than 20 million Americans are estimated to have asthma, an immune disorder that affects the muscles around the bronchial tubes leading to the lungs. In a reaction to certain stimuli, the muscles tighten, narrowing the airways and causing them to become inflamed and clogged. The person finds breathing difficult, and wheezes and coughs. In severe episodes, the person finds it almost impossible to breathe and requires immediate medical attention.
Most asthma attacks are caused by allergies to inhaled substances such as pollen, dust, and animal dander. Food allergies, infections, and emotional stress also can cause attacks. There is no cure for asthma, and proper management is essential. People with the disease can avoid substances and situations that act as triggers. They also can learn to recognize early warning signs and take medications to reduce underlying inflammation and prevent or relieve narrowing of the airways. (Source: NYT Guide to Essential Knowledge)