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 Woman doctor in a medical mask measures the patient's pulse and oxygen saturation to middle aged woman using a pulse oximeter

Is it COPD or asthma?

It's important to know if your symptoms are being caused by asthma or COPD so you can receive the right treatment and know how to manage your symptoms.


COPD vs. asthma

Some people who have asthma are misdiagnosed with COPD and some people are diagnosed with asthma when they actually have COPD. And some people have both asthma and COPD, which is referred to as asthma-COPD overlap syndrome, or ACOS (LINK).


What do COPD and asthma have in common?

Both are obstructive lung diseases, meaning breathing is difficult because of an obstruction or narrowing of the airways. Both COPD and asthma can cause coughing, shortness of breath and wheezing.


What are the differences between asthma and COPD?


  • tends to develop in adults 40 years and older
  • involves inflammation and damage to the structure and function of the lungs
  • often a history of smoking or exposure to smoke
  • symptoms are fairly consistent day to day but gradually get worse over time
  • coughing is more likely to be “productive” (phlegmy)
  • most flareups caused by respiratory infections or air pollution
  • airflow obstruction is not fully reversible
  • co-morbidities caused by lack of oxygen to cells and organs are common
  • goals of treatment are to reduce symptoms, prevent exacerbations and decrease mortality


  • tends to develop earlier in life, often in childhood
  • involves inflammation of the airways
  • often a family history of asthma
  • more likely to also have allergies or rhinitis ("hay fever")
  • symptoms will vary widely from day to day
  • triggered by exercise, allergens or cold air
  • coughing is typically “dry” (not phlegmy)
  • inflammation of the airways can be reversed quickly using an inhaler
  • doesn't cause low blood oxygen levels except in cases of severe asthma attack
  • goals of treatment are to reduce inflammation and control


Diagnosing COPD vs. diagnosing asthma

The results of a lung function test (spirometry) will indicate if your airways are obstructed. Once this is confirmed, your provider will determine if asthma or COPD is the cause. Your provider will consider your medical history including if you have a history of smoking. A history of smoking is more common in COPD.

You may be asked to use an inhaler that reduces inflammation in your airways (a bronchodilator) before repeating the spirometer test. The more "normal" your results after using the inhaler, the more likely it is that you have asthma as the damage caused by COPD is less reversible.

You may also be given medication to try over several weeks before you repeat testing using the spirometer. 

This section was made possible by an unrestricted educational grant from Astra Zeneca Canada.