The air may make a wheezing or whistling sound. These problems occur because the airways of the lungs are getting narrower. The muscles that surround the airways tighten, the inner lining of the airways swells and pushes inward, and the membranes that line the airways secrete extra mucus, which can form plugs that block the air passages. The rush of air through the narrowed airways produces the wheezing sounds that are typical of asthma. Asthma episodes range in severity from slight wheezing, coughing, or problems with breathing, to moderate episodes that can be handled at home, to severe episodes that require emergency treatment from a physician.
Some episodes are life threatening and require immediate medical attention.
The key to asthma management is monitoring one's condition, preventing episodes, and controlling an episode once it starts. To prevent episodes, people with asthma should avoid asthma triggers and should take preventive medication appropriately. If they are to be exposed to a known trigger, such as animals or exercise, they can take medicine beforehand to avoid an attack. To monitor lung function, asthma patients can use a peak flow meter. This is a small, inexpensive device for measuring breathing that can be used at home, at work, or at school.