The exact cause of asthma is still unknown to medical professionals, although they suspect that it may be due to both genetic and environmental factors. These environmental factors can include exposure to triggers such as pollen, dust, mold, and smoke.
With COPD, however, Everyday Health says the cause “is much more clear-cut.” Smoking is far and away the primary reason people develop the disease, and is “attributed to about 85 to 90-percent of all COPD deaths.” The source adds that exposure to air pollution, certain chemicals, and secondhand smoke can also be responsible, as can a genetic defect known as alpha-1 antitrypsin deficiency (AAT), but only in approximately 2- to 3-percent of diagnoses.
As mentioned earlier, asthma is often triggered by exposure to certain substances, like pollen, dust, mold, and smoke. The Lung Institute adds that cold air and physical exercise may also worsen asthma symptoms.
With COPD, the source says symptoms are often triggered by “respiratory tract infections like pneumonia and influenza.” In some cases, however, Medical News Today says “People with COPD may have symptoms when they are active or at rest, without a known trigger.”
While the symptoms of asthma and COPD—such as coughing, wheezing, and shortness of breath—may seem very similar, there are subtle differences. For instance, a chronic cough in people with COPD tends to produce a lot more mucus and phlegm than those with asthma would experience.
Additionally, in those with asthma MedicineNet.com says “breathing can return to normal between attacks,” but with COPD, it typically does not. COPD symptoms also tend to worsen over time, which is less common with asthma.