Asthma is a chronic inflammatory disease that affects the lining of the airways. In some cases, it is also a chronic allergic condition.

The airways become swollen and narrowed and they produce extra mucus. The narrowing causes contractions. Episodes of worsening asthma called asthma attacks occur when the narrowing worsens.

Inflamed Bronchus in the Lungs

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During an asthma attack, symptoms may range from a mild whistling or hissing sound as you breathe to severe obstruction of the airways, potentially causing a life-threatening inability to breathe. Cough-variant asthma begins as persistent, chronic cough without shortness of breath. Although asthma can be serious, there are many ways to prevent and control symptoms.

The underlying cause of asthma is two part: 1) inflammation in the lining of the lung, and 2) structural changes in the lung due to inflammation and narrowing of air passages. Factors in indoor and outdoor environments, called triggers, can make asthma symptoms worse and cause asthma attacks in people who have asthma.

Known asthma triggers include:

  • Allergens:
    • Pollen
    • Mold
    • Animal dander—fine scales from skin, hair, or feathers
    • Dust mites
    • Cockroaches
  • Viral infections of the respiratory tract
  • Irritants:
    • Strong odors or sprays
    • Chemicals, including preservatives containing sulfites and dyes which are in many foods
    • Air pollutants, especially ozone, nitrogen dioxide, and sulfur dioxide
    • Changing weather conditions, especially cold air and dry air
  • Tobacco smoke or wood smoke
  • Drugs, including aspirin and other over-the-counter painkillers in individuals with a special type of asthma
  • Exercise, especially when exertion occurs in a cold environment
  • Emotional stress