Why the Distinction Matters
Asthma and COPD both cause breathlessness, wheezing, and coughing. Patients often receive one diagnosis when they have the other — or both. Getting the diagnosis right is essential because the treatments are different, the prognosis is different, and the lifestyle changes needed are different.
What Is Asthma?
Asthma is a chronic inflammatory condition of the airways. The airway walls become swollen and hypersensitive, causing them to narrow in response to triggers — dust, cold air, exercise, pollen, or smoke. Critically, this narrowing is largely reversible. With the right treatment, the airways can open up and lung function returns to near-normal.
Asthma typically starts in childhood or early adulthood, though adult-onset asthma is increasingly common. It is strongly associated with allergies and a family history of atopy.
What Is COPD?
COPD — Chronic Obstructive Pulmonary Disease — is a progressive condition caused by long-term damage to the lungs, most commonly from smoking. The damage destroys alveoli (air sacs) and narrows the small airways permanently. Unlike asthma, this airflow limitation is not fully reversible. The lungs cannot be restored to normal, though progression can be slowed.
COPD is almost always seen in adults over 40 with a significant smoking history. It includes chronic bronchitis (persistent mucus and cough) and emphysema (destruction of air sacs).
Key Differences at a Glance
| Feature | Asthma | COPD |
|---|---|---|
| Age of onset | Childhood or early adulthood | Usually after age 40 |
| Main cause | Allergies, genetics, environment | Smoking (90% of cases) |
| Airflow limitation | Reversible with treatment | Mostly irreversible |
| Symptoms vary day to day | Yes — often worse at night | More consistent, slowly progressive |
| Response to bronchodilator | Significant improvement | Partial improvement |
| Response to steroids | Excellent | Limited in stable disease |
Can You Have Both? ACOS
Yes. Asthma-COPD Overlap Syndrome (ACOS) occurs in a significant minority of patients — particularly older adults who had asthma as children and smoked. These patients have features of both conditions and need combined treatment strategies. Spirometry and clinical evaluation are essential to identify this group correctly.
How Are They Diagnosed?
Spirometry is the key test. It measures how much air you can breathe out and how fast — available at Respire Airway Clinics — giving an objective measure of airflow obstruction. A bronchodilator reversibility test (spirometry before and after inhaler) distinguishes asthma from COPD with high accuracy. Both tests are available at Respire Airway Clinics and take about 20 minutes.
The Bottom Line
If you have been told you have asthma or COPD but your symptoms are not well controlled, ask for a spirometry review. Misdiagnosis is common — and the right diagnosis leads to the right treatment.