Cause of Asthma

Sarah Jane Rodriguez

July 9, 2021

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(This article first appeared in the July/August 2021 issue of the American Postal Worker magazine)

No one really knows what causes asthma. What we do know is that asthma is a chronic inflammatory disease of the airways. When airways come into contact with a trigger, they become inflamed, narrow and filled with mucus. When people with asthma have an attack, their airways narrow and it gets hard to breathe. This can result in spasms of the muscles around the airways, inflammation and swelling of the mucosal membrane that lines them, or high amounts of mucus inside them. You might have shortness of breath, wheeze or cough as your body tries to get rid of the mucus. While we do not know all the things that can cause asthma, we do know that genetic, environmental and occupational factors have been linked to developing asthma.

Asthma Triggers

If you have asthma, your triggers can be quite different from someone else with asthma. Know your triggers and learn how to avoid them. Some of the most common triggers are: :

  • Tobacco Smoke - Tobacco smoke is unhealthy for everyone, especially people with asthma. “Secondhand smoke” is smoke created by a smoker and breathed in by a second person. Secondhand smoke can trigger an asthma attack.
  • Dust Mites - Dust mites are microscopic bugs that are in many homes. If you have asthma and are allergic to dust mites, they can trigger an asthma attack.
  • Outdoor Air Pollution - Outdoor air pollution can trigger an asthma attack. This pollution can come from many sources, including factories, cars or wildfire smoke. Wildfire smoke from burning wood or other plants is made up of a mix of harmful gases and small particles. Breathing in too much of this smoke can cause an attack. 
  • Pests (e.g., cockroaches, mice) - Cockroaches and other pests are often found where food is eaten and crumbs are left behind.
  • Pets - Furry pets can trigger an asthma attack if you are allergic to them, even if you trim their fur.
  • Mold - Breathing in mold can trigger an asthma attack even if you are not close to it. Indoor mold growth is often found in damp areas such as kitchens, bathrooms, and basements, or in areas where water damage has occurred. There are many types of molds that can be found in any climate.
  • Cleaning and Disinfection - Disinfectants can trigger an asthma attack. Triggers can happen during and right after use.
  • Other Triggers - Infections linked to influenza (flu), colds, and respiratory syncytial virus (RSV) can trigger an asthma attack. Sinus infections, allergies, pollen, breathing in some chemicals and acid reflux can also trigger attacks. Physical exercise; some medicines; bad weather, such as thunderstorms or high humidity; breathing in cold, dry air; and some foods, food additives and fragrances can also trigger an asthma attack.
  • Strong emotions can lead to extremely fast breathing, called hyperventilation, which can also cause an asthma attack.

The APWU Health Plan is dedicated to the education of its members by providing the latest information on all aspects of a healthy lifestyle, including asthma management. Please visit to read blogs and articles on all aspects of living your healthiest life with asthma. Consult with your physician to develop an asthma action plan. For further information, please go to:,,

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