Asthma Flare-ups

Why do I need to worry about flare-ups?

To keep your asthma under control, you need to know what to do when you have a flare-up of symptoms (sometimes called an “exacerbation” or an “asthma attack”). First, you need to know the warning signs of a flare-up. Second, you need to know what to do when your asthma gets worse so you can get it under control quickly.

What causes asthma symptoms to flare up?

Your asthma can flare up for many different reasons. Allergies can make your asthma symptoms get worse. Viral infections (such as a cold), tobacco, pollutants (such as wood smoke), cold air, exercise, fumes from chemicals or perfume, sinus infections and heartburn can all cause a flare-up. For some people, strong emotions or stress can trigger an asthma attack. Pay attention to the way these things affect your asthma. If you and your doctor figure out which things bother your asthma, you can start trying to address them.

What are the symptoms of an asthma flare-up?

Common symptoms of an asthma flare-up are coughing, feeling breathless, a feeling of tightness in the chest and wheezing (breathing that makes a hoarse, squeaky, musical or whistling sound). Watch yourself every day for any of these symptoms.

How do I know how serious a flare-up is?

Your doctor will show you how to keep track of your asthma by using a peak flow meter. This device measures your peak expiratory flow rate (PEFR), or how fast you can blow air out of your lungs. First, you find out your “personal best” peak flow. This is the highest reading you can get on the meter over a 2-week period when your asthma is under good control.

Here are some guidelines on using a peak flow meter to find out how serious an asthma flare-up is:

  • During mild flare-ups, you may feel breathless when you walk or exercise, but feel OK when you sit still. You can usually breathe well enough to talk in complete sentences. You may hear some wheezing, mostly when you breathe out. Your peak flow readings will be 80% to 100% of your personal best.
  • During moderate flare-ups, you may feel breathless when you talk or walk around, but feel better when you sit quietly. You may not be able to finish whole sentences without taking a breath. You may find yourself needing more quick-acting medicine to treat your asthma symptoms as they get worse, or awakening more often at night with asthma symptoms. You may hear loud wheezing, especially when you breathe out. Your peak flow readings will likely be between 50% and 80% of your personal best.
  • During serious flare-ups, breathing will be very difficult. You’ll feel breathless even when you’re sitting still. You might only use a few words at a time because you’re so short of breath. You’ll feel anxious or tense. You continue to get worse even when using your quick-acting medicine to treat your worsening asthma symptoms. Your peak flow readings will likely be less than 50% of your personal best. If you feel very tired and confused, you may be having a life-threatening attack. Serious flare-ups mean you need to be treated right away, preferably in an emergency room.

How is an asthma flare-up treated?

If you feel like you're having a flare-up, use your quick-acting medicine or quick-relief inhaler (sometimes called a rescue medicine) right away. Be sure you and your doctor talk beforehand about how much medicine to take during a flare-up.

To figure out how serious the flare-up is, use your peak flow meter after you use the quick-acting medicine. If your peak flow is less than 50% of your personal best, your flare-up is serious.

Ask your doctor for written directions about treating asthma flare-ups. (Your doctor may have a form to give you, or you can print out this one.) If you have the symptoms of a serious flare-up or if your peak flow is less than 50% of your personal best, call your doctor right away or go directly to the nearest emergency room (by ambulance, if necessary).

More Information

For more information talk to your doctor.

Other Organizations


Written by editorial staff.

American Academy of Family Physicians

Reviewed/Updated: 05/07
Created: 05/01