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Reduce Asthma Triggers

An asthma trigger is a thing, activity or condition that makes asthma worse. When you encounter a trigger it can cause a sudden worsening of symptoms, often called an asthma attack, episode or flare-up.

Common asthma triggers include respiratory infections, allergens, irritants, exercise and emotions. Knowing what causes your asthma symptoms is an important step toward controlling your asthma. Allergy testing may help you identify your triggers. Your healthcare provider can help you recognize what makes your asthma worse, and help find simple solutions to reduce and avoid asthma triggers.

The most common asthma triggers include:

Medical Conditions

Respiratory Infections, such as a cold, flu or sinus infection, are the most common causes of asthma symptoms leading to asthma flare-ups. Frequent hand washing and avoiding people who are sick will help reduce your exposure to cold and flu. But, the best way to prevent influenza is to get a flu vaccine every year. Medical conditions such as acid reflux can also worsen asthma symptoms.


Food & Medicines

Asthma can be triggered by food allergies and medicines. Discuss any over-the-counter or prescription medicines you take such as aspirin, fever-reducers or anti-inflammatories with your healthcare provider, along with any alternative therapies or herbal remedies that may impact your asthma.


  • Common food allergies (peanuts and shellfish)
  • Aspirin
  • Non-steroidal anti-inflammatory drugs


All types of smoke can make it hard to breathe, including smoke from cigarettes, wood-burning fireplaces and burning leaves. If you smoke, you should make a plan to quit. If you don't smoke, but live with someone who does, discuss ways to avoid or limit your exposure to tobacco smoke. The American Lung Association offers many ways to help smokers quit. Contact the American Lung Association Lung HelpLine at 1-800-586-4872 to speak with a smoking cessation counselor.


  • Cigarette, cigar or pipe smoke
  • Fireplace, campfire or leaf-burning smoke

Weather, Pollen & Air Pollution

Changes in the season can bring on an asthma episode due to increased pollen in the air. Limit your time outdoors during high pollen times of the year such as spring and fall. Also, extreme temperatures (hot and cold) can trigger asthma symptoms. Prepare for the weather before you leave your home by checking the pollen count and air quality index.


  • Cold, windy or stormy weather
  • Sudden or extreme temperature changes
  • High humidity
  • Weeds, trees and grass
  • Air pollution, smog, vehicle exhaust and fumes


Dander and saliva from animals with fur or feathers can be an allergen for some and can cause asthma symptoms. Reduce your exposure to pet allergens by vacuuming and damp dusting weekly. Try to keep your pets out of the bedroom or other rooms where you spend a lot of time. You might also consider bathing and changing clothes after playing with furred pets. 


  • Birds
  • Cats, dogs, ferrets, hamsters, Guinea pigs, bunnies or mice


Pests in the home, workplace or school can impact your asthma. To reduce your exposure, wash bedding regularly, fix leaks, store garbage outside, vacuum and dust weekly. If you're allergic to dust mites, use allergen-proof pillows and mattress covers.



Mold is an allergen that can trigger asthma symptoms. You can reduce your exposure to mold by cleaning visible mold, throwing away moldy items, running a dehumidifier and using the exhaust fan when taking a shower. Clean mold with mild soap, hot water and a strong brush.


Staying active is very important to your overall health and wellbeing, especially for those with asthma. If exercise causes your asthma symptoms, use your quick-relief medicine 15 to 30 minutes before physical activity if prescribed. Remember to monitor the air quality if you plan to exercise outside.


  • Walking, climbing stairs
  • Intense exercise
  • Sports
  • Swimming


Every day comes with its ups and down emotionally. It's important to remember that strong emotions can increase rapid breathing and trigger asthma symptoms. Stress, both personal and work-related, can be a major trigger as well.


Strong Odors

Scents from perfumes, deodorants and cleaning supplies can affect a person with asthma. When possible, choose cleaning and personal care products that are odor- and fragrance-free.


  • Cleaning products
  • Gas Stoves
  • Scented candles and incense
  • Hairspray
  • Air fresheners
  • Personal care products
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Download our Avoiding and Controlling Your Asthma Triggers worksheet: English | Spanish

    Reviewed and approved by the American Lung Association Scientific and Medical Editorial Review Panel. Last reviewed May 21, 2018.

    Page Last Updated: April 30, 2019

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