The Differences Between COPD and Asthma

Woman using inhaler at doctor's office
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The difference between COPD and asthma really lies in the pathophysiology or the physical processes that lead to asthma symptoms. Both asthma and COPD result from inflammation and hyperactivity, but COPD inflammation results from macrophages and neutrophils (two types of white blood cells that are part of the immune response) and develops over many years. Inflammation from asthma, on the other hand, most commonly occurs over a shorter period and results from eosinophils (another type of white blood cell).

Asthma and COPD both involve chronic inflammation that leads to airflow obstruction. Asthma and COPD may have similar symptoms, such as:

Both diseases can be exacerbated by things such as viral infections, exposure to tobacco smoke and other indoor air pollutants, environmental pollution, or occupational exposures. Both conditions are diagnosed with breathing tests called spirometry.

There are differences, however. Asthma is a disease in which your airways become inflamed and irritable in response to an allergen. When this happens it becomes more difficult to move air in and out of your airways, which leads to asthma symptoms. Asthma and COPD are treated and respond to treatments differently because the cause of inflammation is different. The goals of treatment in asthma and COPD are also different. In asthma, your doctor will attempt to lower or suppress inflammation, while the goal on COPD is to reduce symptoms.

In COPD, your lungs become damaged following exposure to certain irritants, most commonly due to chronic cigarette smoking. This chronic exposure and damage lead to airway obstruction and hyperinflation. While airflow in asthma is mostly reversible, airflow in COPD is only partially reversible or may not be reversible at all. Inflammation in COPD is not due to allergens, but more commonly due to bacteria.

More Differences

There are a number of other differences between COPD and asthma:

Age - An easy difference between COPD and asthma is the age when a diagnosis is made. Asthma is most often diagnosed in childhood or adolescence, while COPD is diagnosed later in life. This does not mean that you cannot be diagnosed with asthma as an adult, it is just less likely.

Smoking history - Nearly all patients with COPD either have smoked or have had a significant environmental tobacco smoke exposure, while asthma patients are more commonly non-smokers. Surprisingly to me, nearly 1 in 4 asthmatics smoke which can lead to exacerbations of asthma and deteriorating lung function.

Symptoms - Another difference between asthma and COPD is the intermittent symptoms seen with asthma versus the chronic, progressive symptoms seen in COPD.

Forced Expiratory Volume (FEV1) Changes - Reversibility of FEV1 represents another difference between asthma and COPD. In asthma, decreases in FEV1 return to normal between asthma attacks, while changes in FEV1 in COPD are generally not reversible.

Common coexisting conditions - In asthma, you will commonly have coexisting allergic conditions such as allergic rhinitis or eczema, while COPD patients will have smoking-related diseases like coronary heart disease or osteoporosis.

Inhaled steroids - While inhaled steroids are considered standard care in all stages of asthma beyond intermittent asthma, inhaled steroids only benefit a small number of patients with COPD.

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