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What Is Asthma?

Asthma (pronounced: AZ-muh) is a lung condition that makes it hard to breathe. Lots of people have asthma, from young kids to the elderly.

What Causes Asthma?

No one knows exactly why some people develop asthma. Experts think it might be a combination of environmental factors and genes.

People with asthma may have a parent or other close relative with asthma. Those who are overweight may be more likely to have it.

Asthma isn't contagious. You can't catch it from someone who has it.

How Asthma Affects Breathing

With normal breathing, air flows in through the nose or mouth and then into the windpipe (trachea). From there, it passes through the airways (bronchial tubes), into the lungs, and finally back out again.

In people with asthma, the airways are (swollen) and produce lots of thick mucus. Inflamed airways are also very sensitive, and things like dust or smoke can make the muscles around them tighten up. All these things can narrow the airways and make it harder for a person to breathe.

What Are the Signs & Symptoms of Asthma?

Asthma Flare-Ups

An asthma flare-up (or "attack") is when a person's symptoms get worse. During a flare-up, a person might have:

  • trouble breathing
  • a tight chest
  • a whistling sound when breathing (wheezing)
  • a cough

Things that bring on a flare-up are called triggers. These can vary, but common triggers include:

  • allergens, like pollen, mold, or other things that cause an allergic reaction in some people
  • airborne irritants and pollutants, like smoke, strong scents, or high levels of air pollutants
  • exercise
  • weather, like cold, dry air or extreme heat or humidity
  • respiratory tract infections, like colds and the flu

Other things can trigger asthma flare-ups too: Some girls find their asthma gets worse just before their periods. Even laughing, crying, and yelling can sometimes make the airways tighten.

Many people with asthma compare a flare-up to the feeling of trying to breathe through a straw — it feels very hard to get air in and out of their lungs.

An asthma flare-up can last for several hours (or longer if a person doesn't use asthma medicine). When a flare-up is over, the person usually feels better. Between flare-ups, breathing can seem completely normal, although some people may cough or feel as if they are always short of breath.

  • Asthma Flare-ups: What Happens

    Asthma Flare-ups: What Happens

    Learn what asthma is, what happens during an asthma flare-up, and how to control and live with asthma.

How Is Asthma Diagnosed?

To diagnose asthma, a doctor will do a physical exam and ask about the person's medical history, including whether anyone else in the family has asthma.

The doctor might do tests like spirometry (pronounced: spye-RAH-muh-tree) or peak flow meter tests. These involve blowing into devices that can measure how well the lungs are working. Allergy tests or exercise tests can tell doctors if asthma is brought on by allergens or physical activity. Doctors may use X-rays to rule out other problems.

How Is Asthma Treated?

There's no cure for asthma, but it can be managed to prevent flare-ups. Asthma treatment involves two important components: avoiding triggers and taking medicine.

Avoiding Triggers

People with asthma need to avoid the things that might cause flare-ups. Of course, some triggers can't be completely avoided (like catching a cold). But exposure to other triggers, such as pet dander, can be controlled.

Keep your environment clear of potential allergens, like dust or secondhand smoke. Don't smoke (or quit if you do). Pay attention to the weather and stay indoors or limit your exercise to indoor activities when you know weather or air pollution may affect you.

Doctors help people with exercise-induced asthma manage physical activity, not avoid it. Exercise can help people stay healthier overall. Doctors can help people find treatments that allow them to them participate in their sports — in fact, many professional athletes have asthma.

Taking Medicine

Most asthma medicines are breathed directly into the lungs (inhaled), but some are pills or liquids. There two types of medicines are:

  1. Quick-relief medicines, which act fast. They can be used as needed during a flare-up. Quick-relief medicines act fast, but their effect doesn't last long. These kinds of medicines are also called "fast-acting" or "rescue" medicines.
  2. Long-term control medicines, which manage asthma and prevent symptoms from happening in the first place. Many people need to take daily medicines to manage asthma. These medicines help prevent flare-ups before they start. They work differently from quick-relief medicines because they treat the problem of airway inflammation instead of the symptoms (coughing, wheezing, etc.) that it causes. These medicines are also called "controller" or "maintenance" medicines.

    Long-term control medicines can take days or even weeks to start working. Their regular use should lessen the need for quick-relief medicines, but they need to be taken every day or they can't do their job.

Some people with asthma only need quick-relief medicine; others need both kinds of medicine to keep their asthma in check.

Asthma care can seem overwhelming, especially at first. That's why people with asthma need to work closely with a doctor to create an asthma action plan that's right for them. The written plan will say when to take medicines, what triggers to avoid, when to go to the ER, and more. Refer to your plan often.

What Else Should I Know?

The best way to manage asthma is to prevent flare-ups. Do that by following your asthma action plan and avoiding triggers, taking any medicines your doctor prescribes as directed, and getting a flu shot each year.

Your doctor also may ask you to keep track of your asthma symptoms in an asthma diary. This can help the doctor track how you feel after taking medicines. Your doctor might also ask you to use a peak flow meter as a way to monitor your asthma.

Caring for asthma takes a bit of work. But if you follow your asthma action plan, take your medicines properly, recognize your symptoms and triggers, and check in with your doctor regularly, you can do anything that people without asthma do.

Reviewed by: Okan Elidemir, MD
Date reviewed: February 2019