[Skip to Content]

What's an Asthma Flare-Up?


When people have asthma, their airways are always a little swollen or irritated. Airways are the tiny breathing tubes in a person's lungs.

What's an Asthma Flare-Up?

During an asthma flare-up (also called an asthma flare, attack, episode, or exacerbation), asthma problems get worse. Sticky mucus clogs the airways. The muscles around them tighten up. That narrows the breathing tubes. Picture a straw with walls that are getting thicker and narrower, leaving less and less space inside for air to get through.

A person who is having a flare-up might:

If a flare-up is severe, the person may struggle to breathe even while sitting still. Someone having a severe flare-up may not be able to speak more than few words without stopping to breathe.

What Happens During an Asthma Flare-Up?

Asthma flare-ups can be dangerous — and scary. You have to act fast! Someone having an asthma flare-up might need to take quick-relief medicine, visit the doctor, or even go to the hospital.

Having a set of instructions called an asthma action plan helps you know what to do.

What Causes Asthma Flare-Ups?

Things like smoke or perfume can bring on breathing problems for people with asthma. These are called triggers.

Different people have different triggers. For some people a trigger may be cold air, exercise, or infections (like colds). For others triggers might be allergens like animal dander, dust mites, or mold.

Triggers can cause flare-ups because they make the swelling in the airways worse and increase the amount of mucus. Triggers also can cause the muscles around the airways to tighten, making the airways even narrower.

If a flare-up isn't treated it can last for several hours or even days. Quick-relief medicines (inhalers or "puffers") often take care of the symptoms pretty fast. Most people feel better after a flare-up is over, though it can take several days to completely clear up.

How Can I Spot an Asthma Flare-Up?

You can predict some flare-ups, but it might take a bit of detective work.

Some flare-ups happen suddenly, after a person is exposed to a trigger — like being around someone who is smoking. Flare-ups also happen when problems in the airways build up over time. That can happen when a person's asthma is not well controlled.

Flare-ups need to be treated at their earliest stages. So it's important to know early warning signs (things that someone might notice just before a flare-up happens).

Clues that a flare-up might happen are different for everyone. They might even be different with each asthma flare-up.

Early warning signs include:

Some doctors tell people with asthma to use a peak flow meter as a way to help predict if a flare-up is on its way.

Can I Prevent Asthma Flare-Ups?

You have the power to prevent flare-ups, at least some of the time. Here's what you can do:

Date reviewed: January 2014


Note: All information on TeensHealth® is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.

© 1995- The Nemours Foundation. All rights reserved.

Images provided by The Nemours Foundation, iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart.com