What's the Difference Between COPD and Asthma?

Health Professional

When you're short of breath, there's no mistaking it. It's clear to see - and feel. But what, exactly, is going on inside the lungs to cause it? And how do different obstructive lung disorders compare? Today we'll look at a common question asked by people with COPD.

How are they the same?
Before we talk about what's different, let's look at what COPD and asthma have in common. They both cause shortness of breath, coughing and wheezing, and they are both obstructive lung diseases, meaning that you have trouble getting your air out. (This is different than restrictive lung disease causing difficulty in getting the air in. One commonly known restrictive lung disease is pulmonary fibrosis, in which there is scarring of the lung tissue. Restrictive lung disease can also be mechanical in nature; such as with chest wall abnormalities, respiratory muscle impairment, or neuromuscular disease. )

What is COPD?
COPD, or Chronic Obstructive Pulmonary Disease, is an umbrella term used to describe progressive lung diseases including emphysema, chronic bronchitis, refractory (non-reversible) asthma, and some forms of bronchiectasis. This disease is characterized by increasing breathlessness.

What is Emphysema?
Emphysema is a disease in which there is permanent damage to the alveoli. The alveoli are the millions of tiny, elastic air sacs at the very ends of the smallest tubes in the lungs. In emphysema the alveoli become stretched out, and lose their elasticity.   Their walls break down, reducing the lungs' ability to exchange oxygen and carbon dioxide. Stale air becomes trapped in the lungs and they expand permanently, becoming too large and causing crowding within the chest. This leads to an increase in work of breathing that is less effective than in healthy lungs.

What is Chronic Bronchitis?
In Chronic Bronchitis there is inflammation (swelling) of the lining of the bronchial airways, causing difficulty with air flowing in and out of the lungs. When the bronchial tubes have been irritated over a long period of time, two major changes take place: 1.) the lungs produce excessive mucus and 2.) the lungs' natural cleaning mechanism is hindered or disabled resulting in mucus getting stuck in the airways. This forms an ideal breeding ground for infections. Chronic bronchitis is defined by a mucus-producing cough on most days of the month, three months out of a year, for two successive years with no other explanation for the cough.

What is Asthma?
Asthma is both an inflammatory and a spastic disease of the bronchial airways.   Inflammation (swelling) of the inside lining of the airways causes narrowing, making it harder for the air to flow through. Spasms of the muscles around the airways (squeezing)   also leads to difficulty breathing.   Inflammation in the airways makes them very sensitive, and prone to react strongly to irritants and allergens.

How these diseases affect me, and what makes them different?
The main difference between COPD and asthma is that asthma is usually completely reversible. This means that with treatment, a person with asthma can have near-normal lung function and be free of symptoms between episodes / flare-ups. Asthma episodes with wheezing, shortness of breath, chest tightness and cough often have triggers that can be identified easily. These triggers can be seasonal or other allergens, airborne irritants such as smoke or dust, strong odors or chemicals, cold air or exercise.

COPD is characterized by airflow obstruction that is only partially reversible, or completely non-reversible.   People with partial reversibility don't usually experience the same level of improvement with medications as do people with asthma. A person with COPD will always have a lung function results lower than normal, even when not sick with an episode / flare-up (exacerbation).   As indicated by the name, COPD is a chronic disease. It is always there even when you're feeling well. It does not go away.

Another difference is that although episodes /flare-ups, (exacerbations) in people with COPD can be brought on by irritants in the air, they are more commonly caused by bacteria or virus in the respiratory tract.

It is sometimes thought that an easy way to tell the difference between COPD and asthma is the age when a diagnosis is made - that asthma is most often diagnosed in childhood, adolescence, or early adulthood while COPD is diagnosed later in life. But this is not always the case. It's common for the genetically-inherited cause of COPD, Alpha-1 Antitrypsin Deficiency, to be mistaken for asthma in a younger person.

Is it possible to be diagnosed with both COPD and asthma?
Yes. It is not unusual for a person to have all these things going on in the lungs: Damage of the alveoli with over-inflation, frequent cough with increased mucus production, and reversible airway constriction.   It is for this reason that people with COPD may be on several inhaled medications and / or combination meds. Each class of medication works to open the airways of the lungs in its own way.

Jane M. Martin is a licensed respiratory therapist, teacher and the founder and director of http://www.Breathingbetterlivingwell.com and the author of Live Your Life With COPD: 52 Weeks of Health, Happiness and Hope and Breathe Better, Live in Wellness: Winning Your Battle Over Shortness of Breath.