What causes asthma?

Asthma seems to be an allergic reaction triggered by something breathed into the lungs or due to some other problem occurring in the body. Inhaled "triggers" can be due either to specific allergies or to irritants.

Allergens (things causing specific allergic reactions) include:

  • Dander (flakes) from the skin, fur, or feathers of pets (usually cats or dogs)
  • Pollen from trees, grasses, or weeds
  • Dust mites
  • Cockroach waste
  • Molds (indoor or outdoor)

Irritants (non-specific inhaled triggers) include:

  • Smoke from cigarettes or wood fires
  • Perfumes
  • Chemical fumes, including household cleaners and detergents
  • Scented hairsprays and cosmetics
  • Strong odors from fresh paint or cooking
  • Automobile exhaust fumes
  • Air pollution, including ozone
  • Chalk dust or other powder dust

Non-inhaled triggers of asthma attacks include:

  • Viruses or bacterial infections such as head colds or bronchitis
  • Heartburn (also called reflux)
  • Medications, including aspirin and the beta blocker type of heart medicines
  • Exercise, especially in cold weather
  • Stress and strong emotions like crying or joy
  • Foods like shrimp or peanuts
  • Food additives, such as sulfites used to preserve shrimp, dried fruit, or beer

For a person with asthma, understanding your personal triggers is key. Avoid them as much as possible. Starting treatment before an exposure or getting treatment as soon as possible after an exposure can mean the difference between mild, controlled disease and severe, life-threatening disease.

To learn more:

Asthma Triggers: Gain Control
(Environmental Protection Agency)
This site explains and lists common indoor asthma triggers.
Mold: Basic Facts
(Centers for Disease Control and Prevention (CDC))
A fact sheet on molds from the Centers for Disease Control explains the different kinds of molds, how they affect people, how to find out if you have this problem and what to do about it.
Occupational Asthma
(American College of Allergy, Asthma & Immunology)
Allergy, Asthma and Immunology Online gives you information about how to find out if you have job-related asthma.

next » What are the signs and symptoms of asthma?

Written by: Lillian Trettin, Ph.D.
Reviewed by: Jeffrey G. Schultze, M.D.
Last Modified: Tuesday April 07, 2015 10:28 AM