Differential Diagnosis

Asthma vs. COPD

Differential DiagnosisSpirometry is crucial to the early and accurate diagnosis of asthma and COPD. Expiratory airflow obstruction is the cardinal sign of both asthma and COPD. Once airflow obstruction is determined with spirometry, the next step is to determine the underlying cause and differentiate between asthma and COPD. Although they are distinct illnesses, the pathologic features and clinical presentation are similar.

The distinction between asthma and COPD can usually be made based on patient history, clinical symptoms, and spirometry data. The information on this page may be of assistance in determining the differentiation of asthma and COPD.

Smoking has been shown to be the principal cause of COPD as opposed to asthma, which is often hereditary and is not associated with the inhalation of an irritant.

Patients with asthma experience reversible, recurrent episodes of coughing and wheezing associated with chest tightness and shortness of breath. Asthma patients often suffer from hay fever and have a tendency toward atopy. COPD patients suffer from a chronic productive cough and progressive shortness of breath that is not fully reversible with medication.


COPD Asthma
  • Onset in mid-life
  • Symptoms slowly progressive
  • Long smoking history
  • Dyspnea during exercise
  • Airflow reversibility minimal if any
  • Onset early in life (often childhood)
  • Symptoms vary from day to day
  • Symptoms at night/early morning
  • Allergy, rhinitis, and/or eczema also present
  • Family history of asthma
  • Airflow obstruction largely reversible

Note: This information is intended to augment, not replace, a physician’s independent professional judgment.


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