What Is It?

Asthma is a chronic (long-term) lung condition that causes breathing difficulties and wheezing when air passages narrow and become inflamed. The condition ranges from mild to severe. Some people have only occasional, mild symptoms, while others have nearly constant symptoms with severe, life-threatening flare-ups.

During an asthma attack, the airways become inflamed and narrower as the muscles surrounding them constrict. The flow of air is blocked partially or completely as mucus produced by the inflammation fills a narrower passageway. Asthma affects both the lung's larger airways, called the bronchi, and the lung's smaller airways, called the bronchioles. Treatment focuses on preventing or stopping the inflammation, and relaxing the muscles that line the airways.

What causes asthma-related inflammation is not clear, but several environmental "triggers" have been identified. Many asthma triggers are allergens, substances that cause the immune system to overreact in some people. Common allergens include animal dander and saliva, pollens, molds, dust mites, cockroaches, some medications and certain foods. Also high on the list of asthma triggers are viral infections, such as colds and influenza; exercise; breathing cold, dry air; environmental pollutants, such as cigarette smoke, wood smoke, paint fumes and chemicals; strong odors; and emotional stress. For some people with severe asthma, no specific triggers can be identified.

Although asthma can develop early, often before age 5, its symptoms can begin at any age. The condition has a genetic (inherited) component and often affects people with a family history of allergies. The American Lung Association estimates that 25 million people in the United States will be diagnosed with asthma in their lifetime. One-third of Americans with asthma symptoms are children.

Symptoms

Symptoms of asthma include:

• Wheezing (a whistling sound as air is forcibly expelled)

• Difficulty breathing

• Chest tightness

• A persistent cough

For some people with asthma, a chronic cough is the main symptom. For some people, symptoms flare up only during or after exercise. Between asthma attacks or flare-ups, people with mild or moderate asthma may not have any symptoms. People with asthma tend to have more severe symptoms when they have an upper respiratory infection such as a cold or the flu.

In addition to extreme shortness of breath and chest tightness, symptoms of a severe asthma attack can include:

• A rapid pulse

• Sweating

• Flared nostrils and pursed lips

• A need to sit upright

• A bluish discoloration of the lips and fingernails (cyanosis)