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What Is Asthma?

Asthma is a long-term (chronic) lung disease. The airways become inflamed. The airways may be sensitive to:

  • Allergens. These are things that cause allergic reactions, such as dust or pet dander.

  • Irritants. These are things in the air, such as tobacco smoke or pollution.

  • Other. These are things like weather changes or respiratory infections.

These things trigger changes in the airways. In asthma, airway changes include:

  • Swelling of the lining

  • Tightening of the muscles around the airways

  • Increased production of sticky mucus

All of these things cause the airways to narrow. This makes it hard for air to go in and out of your lungs.

These changes in the airways cause asthma symptoms. Common symptoms of asthma are:

  • Trouble breathing

  • Chest tightness

  • Wheezing or whistling sound when breathing

  • Coughing

Asthma differences

Asthma varies from person to person. It can also change over time for each person. The differences are:





  • Triggers are things that make asthma worse.

  • Some people may have only 1 trigger. Others may have many.

  • Some triggers may be allergens or irritants, or a combination.

  • In some people asthma may get worse with exercise, extreme emotions, season changes, or other illnesses.



  • You may have all of the common symptoms.

  • You may only have 1 symptom, such as coughing.

Severity of symptoms


  • May be mild. They don’t interfere with daily activities.

  • May be moderate. They interfere with some activities.

  • May be severe. They interfere with work or school and make it hard to sleep. May need frequent emergency room visits or stays in the hospital.

Frequency of flare-ups


  • Flare-ups are when symptoms get worse.

  • Some people may never have flare-ups.

  • Some people may have them once in a while.

  • Some people may have them very often.

Control of symptoms


  • Some people have few symptoms if they stay away from triggers.

  • Some people need to take medicines.

  • Some people have trouble, even if they stay away from triggers and take medicines.

Facts about asthma

  • Asthma has no cure. But most of the time, symptoms can be controlled.

  • An Asthma Action Plan is key to good asthma control. It is a personal worksheet created by you and your healthcare provider. It shows what to do if you have asthma symptoms. It also tells you when to call your provider or when to call 911. And when to go to the emergency room.

  • It affects all ages, from babies to older adults.

  • It can start at any age. Some people have asthma as children, but outgrow it. Some people get asthma as adults.

  • Experts don't know for sure what causes asthma. They think it is caused by a mix of things. Some are inherited and some are environmental.

Online Medical Reviewer: Allen J Blaivas DO
Online Medical Reviewer: Daphne Pierce-Smith RN MSN
Online Medical Reviewer: Marianne Fraser MSN RN
Date Last Reviewed: 2/1/2021
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