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How do Asthma and COPD Differ?

How do Asthma and COPD Differ?

Asthma and COPD are similar diseases. They both are obstructive airway diseases. They both cause similar symptoms. They are both treated with inhalers. But, there are also some key differences between these two diseases. So, how do they differ? Here’s what to know.

Asthma and COPD both have airflow limitation in common. This airflow limitation is caused by airways that become obstructed. When airways are obstructed, this limits the flow of air through them. This is referred to as airflow limitation. The degree of airflow limitation determines how short of breath a person becomes.

So, they are both categorized as obstructive airway diseases. They both cause airflow limitation. And, as noted, they are both treated with similar medicines.

So, how do asthma and COPD differ?

Airflow limitation

Asthmatics tend to only have airflow limitation during flare ups, which are usually referred to as asthma attacks. These attacks are reversible with time or treatment. So, between attacks, lung function should be normal or close to normal. Therefore, asthmatics are usually only short of breath during asthma flare-ups.

COPD also presents with airflow limitation. However,  unlike asthma, it tends to cause some degree of airflow limitation all the time. So, this this means that symptoms may always be present to some degree.


Also unlike asthma attacks, COPD flare-ups are only partially reversible with time or treatment. So, between flare-ups, lung function remains low. Therefore, COPDers may experience some degree of shortness of breath between flare-ups.

This is where the “Chronic” comes from. This is why it’s referred to as “Chronic Obstructive Airway Disease.” This is opposed to a simple “Obstructive Airway Disease.”

What are some other key differences?

Asthma is caused by an overactive immune response

Researchers think this is due to asthma genes. These genes tell immune cells to recognize otherwise innocuous (harmless) substances in the air as harmful. These immune cells initiate an all out assault on these substances. This results in the release of chemicals that cause airway inflammation. This inflammation is what causes asthma symptoms.

COPD is caused by chronic exposure to noxious chemicals

Day after day after day after day exposure to these noxious chemicals irritate airways. This initiates a response from the immune system. Mediators are released to get these chemicals out of the lungs. These “mediators” cause inflammation of airways and other lung tissue. This is what causes chronic bronchitis and emphysema. Unlike asthma, both of these diseases are progressive, meaning they may slowly get worse over time.

The type of inflammation may be different for both

Asthma inflammation tends to be eosinophilic. This type of inflammation responds well to corticosteroids. Asthma is also reversed with medicines that dilate airways. So, bronchodilators called  beta 2 adrenergics are also helpful. Often, combination inhalers provide both types of medicine. These may help asthmatics obtain good control of their disease. This means they should be symptoms free on most days.

COPD causes chronically obstructed airways

This may be due to airways that are drawn taught due to emphysema. It may be due to airway inflammation. This inflammation may be eosinophilic such as in asthma. This may be reversible with corticosteroids. But, inflammation may be neutrophilic and less responsive to corticosteroids. COPD inflammation may also respond to another type of bronchodilators called muscarinics. There are other treatments to help allay symptoms and slow the progression of the disease.

How are they differentiated?

In other words, how do doctors tell them apart?

Doctors can usually differentiate the two by asking you questions. Do you have a family history of asthma? COPD? Do you smoke? Did you have a job that exposed you to dust, fumes, or chemicals. When do you have symptoms? How often? They may also perform tests. The best test is a breathing test called a PFT. This is a test that measures your lung function. If lung function improves after using a bronchodilator, this usually indicates asthma.

What to make of this? There are certainly other differences, other than those listed here There are also asthmatics diagnosed with severe asthma. They may present similarly to COPD. There are also those who have a combination of both, Asthma-COPD Overlap Syndrome.” There is also a lot more to learn about both.

This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.


  • rhonda61hobo
    2 months ago

    Good read Leon,
    Asthma and COPD Difference

  • Leon Lebowitz, BA, RRT moderator
    2 months ago

    Hi rhonda – glad you found the recommendation to be helpful. Wishing you well, Leon (site moderator)

  • pat02
    6 months ago

    I was diagnosed with Bronchiectasis when I was 8 years old, I spent almost four months in the hospital and had my lower left lobe removed. I did well until I was 18 and then I developed Asthma, for years I fought infections and was in and out of the emergency rooms and hospitals. Then when I was 60 years old I was in and out of doctor offices until my primary care sent me to the pulmonary doctor I am with now and he ran several test and concluded that Bronchiectasis had returned and was in both lungs, I was immediately put on oxygen 24/7. After 5 years my doctor was able to stop the oxygen, I was a happy person, when I was 65 I had to go back on oxygen 24/7 and have been told I am in “Respiratory Failure” I am now 71 and I am not able to do a lot but my husband and kids help me a lot. I feel blessed to have had so many healthy years and I am not ready to call it quits. I have found out that a lot of my issues were inherited and I stay on my kids about taking care of themselves. Hope my experience will help the younger people who have COPD that it is not a death sentence, just get a good pulmonary doctor and keep fighting it, I always say “Just Breathe”
    Have a blessed week.

  • Leon Lebowitz, BA, RRT moderator
    6 months ago

    Hi patO2 and thanks so much for sharing your extensive medical conditions so candidly with the community. You’ve had quite a lifetime of experiences and we appreciate you taking the time to write them down for us to read. “Just Breathe” is a great mantra! Wishing you well, Leon (site moderator)

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