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What Is Asthma?

Asthma is a long-term disease of the lungs where the airways become inflamed. The airways may be sensitive to:

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

  • Irritants. These are things in the air, like 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 surrounding them

  • Increased production of sticky mucous

All of these factors cause the airways to narrow. This makes it difficult 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

Normal Airway


Flare Up

Asthma differences

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




  • Triggers are those things that cause asthma to get worse.

  • Some people may have only 1 or 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.


  • May have all of the common symptoms

  • May only have 1 symptom, like 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 difficult to sleep. May require 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 medications.

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

Facts about asthma

Here are some interesting facts about asthma:

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

  • An Asthma Action Plan is central to good asthma control. It is an individualized worksheet developed by you and your healthcare provider that shows what to do if you have asthma symptoms. It also tells you when to call your healthcare provider or 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 develop asthma as adults.

  • No one is sure what causes asthma. It is believed to be a combination of factors, some inherited and some environmental.

Online Medical Reviewer: Blaivas, Allen J., DO
Online Medical Reviewer: Fraser, Marianne, MSN, RN
Date Last Reviewed: 11/1/2016
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