The common features of asthma and COPD can be used in distinguishing asthma from COPD. “A careful history that considers age; symptoms (in particular, onset and progression, variability, seasonality or periodicity, and persistence); history; social and occupational risk factors (including smoking history, previous diagnoses, and treatment); and response to treatment.”
| Feature | Asthma | COPD |
| Age | Onset before age 20 years | Onset after age 40 (if the onset much sooner, consider alpha-1 Antitrypsin deficiency) |
| Symptom variability/persistence | Symptoms vary over time, often limiting activity Symptoms vary either seasonally or from year to year A record (e.g., spirometry, PEF) of variable airflow limitation |
Symptoms are persistent despite treatment |
| Symptoms improve spontaneously or have an immediate response to bronchodilator tx or ICS over a period of weeks | Symptoms worsen slowly over time (i.e., over a period of yrs) Limited relief from rapid-acting bronchodilator treatment |
|
| PFTs | Lung function that may be normal between symptoms | Abnormal lung function between symptoms |
| Risk Factors | Atopy. FHx of asthma or other allergic condition | Exposure to tobacco smoke, biomass fuels, etc. |
| CXR | Normal chest X-ray | Severe hyperinflation or other changes on chest X-ray |
ICS = inhaled corticosteroids
Reference / Resource
https://www.aafp.org/dam/AAFP/documents/news/COPD-Asthma_Phys_Ed_Booklet.pdf