Understanding Asthma Triggers

Understanding Asthma Triggers

Triggers are substances or conditions that trigger your asthma. Some triggers you can avoid completely. Others you can anticipate and adjust to. Use this sheet to help you identify your triggers.

Man holding a light brown pomeranian dog.

What Are Triggers?

Triggers irritate your lungs and lead to asthma flare-ups. They include:

  • Irritants, such as tobacco smoke or air pollutants. These are a concern for all people with asthma.

  • Allergens (substances that cause allergies). If you have allergies, being exposed to your allergens can trigger a flare-up.

  • Special conditions, such as being ill with a cold or the flu, or certain kinds of weather. These differ from person to person.

  • Exercise can trigger asthma in some people. But it’s the one trigger you don’t want to avoid! If you have exercise-induced asthma, you can learn how to exercise safely.

What Triggers Your Asthma?

Some triggers are common to most people with asthma. Others affect only some people. Which of these common triggers cause you problems? Check all that apply to you. (If you have not been tested for allergens, check what you think triggers your asthma.)


Checkbox. Tobacco smoke

Smoke from fireplaces

Vehicle exhaust


Aerosol sprays

Other air pollutants

Strong odors, such as perfume, incense, or cooking odors

Household cleaners, such as ammonia or bleach




Other furry animals


Dust mites




Other Triggers:

Cold air

Hot air

Weather changes


Certain food additives (such as sulfites)

Certain over-the-counter and prescription medications

Emotions, such as laughing, crying, or feeling stressed

Illness, such as colds, flu, and sinus infections

If You Have Allergies

People with asthma often have allergies. An allergic reaction can trigger a flare-up. If you have allergies, or suspect you have them, talk with your healthcare provider about testing and treatment options. Allergy testing can determine exactly which allergens affect you. Types of tests include:

  • Skin tests. A small amount of each allergen is applied to the skin. Sites are then examined for an allergic reaction (redness, swelling, or itching). In general, the greater the reaction, the stronger the allergy.

  • Blood tests. An allergen is added to a blood sample. If allergy antibodies attack the allergen, it shows sensitivity to the allergen.

Allergy Shots (Immunotherapy)

Exposing a person to gradually increasing amounts of an allergen can help the body build up a tolerance. This is the purpose of immunotherapy. For this therapy, injections are given over a period of 3 to 5 years. At first, injections containing a very small amount of allergen are given about once a week. As treatment continues, the amount of allergen is gradually increased to a maintenance level. Eventually, injections are given less often. This therapy can take up to a year to start working, but can be very effective for long-term management of certain allergies.