Asthma and chronic obstructive pulmonary disease (COPD) can both cause breathlessness and wheezing, but they differ in their causes, course and treatment.
This article explains the differences between asthma and COPD, how doctors distinguish between them, and why lung function tests are an important part of diagnosis.¹
Why can asthma and COPD sometimes be difficult to distinguish?
Because asthma and COPD share some features, telling them apart can sometimes be difficult.²
However, a doctor can determine whether either of these chronic conditions is causing respiratory problems by assessing symptoms and medical history, performing a physical examination and reviewing medical test results.²
What are asthma and COPD?
Asthma
Asthma is a chronic respiratory disease characterised by variable symptoms such as wheezing, breathlessness, chest tightness and cough, together with variable restriction of airflow during exhalation.³
Symptoms and their severity vary over time and with factors such as exercise, exposure to allergens, changes in the weather or viral infections.³
Chronic obstructive pulmonary disease
COPD is a lung condition that causes long-term respiratory symptoms such as breathlessness, cough and sputum production, sometimes interrupted by exacerbations. Changes in the airways or air sacs cause persistent airflow obstruction that may worsen over time.⁴
Asthma versus COPD: key differences¹–³
| Comparison | Asthma | COPD |
|---|---|---|
| Usual age of onset | Usually begins before age 40 | Usually begins after age 40 |
| Triggers and risk factors | Laughter, exercise, allergens and seasonal factors | Smoking and/or other toxic exposures, low birth weight or respiratory disease such as tuberculosis |
| Relationship with smoking | Can affect smokers and non-smokers | Often associated with a long smoking history |
| Symptom pattern | Symptoms vary over time and in severity | Symptoms worsen slowly over time |
| Typical symptoms | Episodes of wheezing and chest tightness, especially at night | May be preceded by cough and sputum, with reduced ability to exercise |
| Symptom improvement | May improve spontaneously or with bronchodilators or inhaled corticosteroids | Bronchodilators provide only limited improvement |
Can one person have features of both asthma and COPD?
The description “asthma with COPD” is used when a patient has persistent airflow limitation alongside clinical characteristics consistent with both asthma and COPD.³
Key characteristics of asthma with COPD include:³
- Intermittent symptoms or symptoms that occur in episodes.
- Symptoms beginning before or after the age of 40.
- A history of smoking or exposure to harmful substances, low birth weight, or previous respiratory disease such as tuberculosis.
- Features suggesting asthma, such as known triggers, improvement spontaneously or with treatment, or a current or childhood diagnosis of asthma.
- Persistent obstruction of airflow during exhalation.
- Airflow may or may not improve after a bronchodilator.
How do doctors distinguish asthma, COPD and asthma with COPD?
1. Medical history and clinical assessment³
The doctor starts by assessing:
- The nature and pattern of respiratory symptoms and whether they are variable and/or persistent.
- A previous diagnosis of asthma, either in childhood or currently.
- Exposure to risk factors, including smoking and/or other factors associated with COPD.
2. Lung function tests¹
Lung function testing is important in helping distinguish asthma from COPD.
During the test, you breathe into a device that measures how much air you can exhale and how quickly. The doctor then gives you an inhaled bronchodilator and repeats the measurement after 15 to 20 minutes.
In asthma:
Lung function usually improves noticeably after a bronchodilator, and airflow obstruction is reversible.
In COPD:
Improvement is limited or absent, and airflow obstruction persists.
In asthma with COPD:
There may be partial but noticeable improvement after a bronchodilator, alongside a clinical picture that does not fully fit asthma or COPD alone.
The breathing-test component may take less than 20 minutes, within a wider assessment that includes clinical review and spirometry with bronchodilator response testing. The doctor may also recommend a chest X-ray or lung CT scan to help with diagnosis and rule out other conditions.¹
Why does the correct diagnosis matter?
Asthma and COPD share some medicines, particularly bronchodilators and inhaled corticosteroids, but their treatment goals and management differ fundamentally.¹
In asthma
Treatment aims to prevent and control asthma attacks. This includes identifying and avoiding personal triggers and using appropriate inhalers.¹
With good asthma control, many patients can be almost free of symptoms between attacks.¹
In COPD
Because changes or damage in the lungs cannot be reversed, treatment focuses on slowing disease progression, reducing the frequency and severity of exacerbations, and preserving remaining lung function as much as possible.¹
When do symptoms require urgent medical assessment?⁵
Seek urgent medical assessment if:
- Your inhaler no longer relieves symptoms as usual, or no longer helps at all.
- Wheezing, cough and chest tightness become severe and persistent.
- Breathlessness prevents you from eating, speaking or sleeping.
- You are breathing faster than usual.
- Your heartbeat becomes rapid.
- You feel drowsy, extremely tired or dizzy.
- Your lips or fingers turn blue.
Conclusion
Asthma and COPD can look very similar, but accurate diagnosis depends on the full pattern of symptoms, exposure to risk factors, lung function testing and the doctor’s interpretation of all this information together, rather than symptoms alone.¹–⁵
Frequently asked questions
Can asthma turn into COPD?
Asthma does not directly turn into COPD. However, asthma that remains uncontrolled for a long time can lead to permanent airway changes and persistent airflow obstruction resembling COPD.¹
Can asthma be cured?
There is currently no permanent cure for asthma, but it is one of the chronic conditions that can be well controlled.¹
Can COPD be cured?
No. Structural changes in the lungs caused by COPD, particularly damage to the air sacs in emphysema, cannot be reversed with current treatments. However, COPD can be managed well.¹
Can someone who has never smoked develop COPD?
Yes. Up to 30% of COPD cases occur in people who have never smoked, and only a small proportion of heavy smokers develop the condition, indicating that other risk factors can contribute.⁶
References
- Sheikh Shakhbout Medical City (n.d.) Asthma vs COPD: What’s the difference and how are they treated? (Accessed: 20 September 2026). Open reference
- American Academy of Allergy, Asthma & Immunology (2026) Asthma and COPD: Differences and similarities. (Accessed: 20 September 2026). Open reference
- Global Initiative for Asthma (2026) 2026 GINA Strategy Report. (Accessed: 20 September 2026). Open reference
- Global Initiative for Chronic Obstructive Lung Disease (2026) Global Strategy for the Prevention, Diagnosis and Management of Chronic Obstructive Pulmonary Disease: 2026 Report. Open reference
- nidirect (n.d.) Asthma. (Accessed: 20 September 2026). Open reference
- National Institutes of Health (2020) Lung development may explain why some non-smokers get COPD and some heavy smokers do not. (Accessed: 21 September 2026). Open reference
