Merck Manual

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    Asthma, or reactive airway disease, is a chronic disorder that results in restricted breathing due to inflammation of the bronchial tubes, the main air passages in the lungs. Asthma affects 3 to 5 percent of adults and 7 to 10 percent of children. Severe asthma attacks cause tens of thousands of deaths per year.

    Three changes occur inside the airways of the lungs in people with asthma: the first change is inflammation, or swelling, whereby the airway becomes inflamed and produce a thick mucus. Inflammation then leads to constriction of the muscles around the airways, causing the airways to become narrow. This narrowing is also referred to as bronchospasm. The third change is increased sensitivity of the airways, causing the asthma patient to become overly sensitive to animal dander, pollen, cold air, and tobacco smoke, to name a few.

    Asthma patients need to work together with their doctors to develop a medication action plan to control symptoms and minimize attacks.

In these topics
Asthma Asthma in Children