Asthma (AZ-muh) is a chronic disease that affects your airways, which are the tubes that carry air in and out of your lungs. If you have asthma, the inside walls of your airways are inflamed (swollen). The inflammation (IN-fla-MAY-shun) makes the airways very sensitive, and they tend to react strongly to things to which you are allergic or find irritating. When the airways react, they become narrow and less air flows through to your lung tissues. This causes symptoms like wheezing (a whistling sound when you breathe), coughing, chest tightness and trouble breathing.

Although asthma cannot be cured, in most patients it can be controlled so that you have only minimal and infrequent symptoms, and you can live an active life. If you have asthma, taking care of it is an important part of your life. Controlling your asthma means staying away from things that bother your airways and taking medicines as directed by your doctor.

By controlling your asthma every day, you can prevent serious symptoms and take part in all activities. If your asthma is not well controlled, you are likely to have symptoms that can make you miss school or work and keep you from doing things you enjoy. Asthma is one of the leading causes of missed school days.

When your asthma symptoms worsen, it is called an asthma episode or attack. During an asthma attack, muscles around the airways tighten up, making the airway openings narrower so less air can flow through. Inflammation increases and the airways become more swollen and narrow. Cells in the airways also make more mucus than usual, which also narrows the airways. These changes cause the symptoms of asthma and make it harder to breathe. Asthma attacks are not all the same; some are worse than others. During a severe asthma attack, the airways can close so much that not enough oxygen gets to vital organs. This condition is a medical emergency. People can die from severe asthma attacks.

If you have asthma, you should see your doctor regularly. You will need to learn what things cause your asthma symptoms to worsen and how to avoid them. Your doctor will also prescribe medicines to keep your asthma under control.

Source: National Heart, Lung and Blood Institute (NHLBI)

Last reviewed April 2008

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