What is an asthma trigger?

Asthma “triggers” are those things that make the airways tighten and become inflamed. Inflammation leads to coughing, wheezing, and difficulty breathing. Sometimes a trigger brings on a reaction right away, but other times it may take several hours or days before symptoms begin.

What are the most common asthma triggers?

There are many kinds of triggers. The most common asthma triggers are:

  • Infections: colds, viruses, sinus infections, flu
  • Weather: cold air or changes in temperature and humidity
  • Allergens: outdoor - pollens (trees, grasses, ragweed and weeds); mold spores ; indoor: molds, animal dander, dust mites, cockroaches
  • Exercise
  • Tobacco smoke
  • Irritants (strong odors from perfumes, cleaning agents, wood smoke, air pollution, etc.)
  • Strong emotions such as anxiety, or episodes of crying, yelling, or laughing hard
  • Certain medications
  • Food allergies (not a common trigger in adults, but can cause asthma symptoms, usually in children under age 5)

Some people are affected by a number of triggers, while others may only have one trigger such as in exercise-induced asthma. It is important to recognize your triggers and avoid them, if possible.

For those triggers you cannot avoid, there are steps you can take to limit your contact and treat your asthma before you encounter them. This is an important step in controlling asthma.

The only trigger you do not want to avoid is exercise. If your asthma is well-controlled, you should be able to participate in any activity you want to do. The information in the document called “Understanding Asthma Triggers” will help you understand how to avoid common asthma triggers.

Last reviewed by a Cleveland Clinic medical professional on 04/27/2017.


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