Which of the following features best distinguishes asthma from COPD in a patient with dyspnea?

• A. Onset in childhood, episodic symptoms, atopy, and reversibility with bronchodilators
• B. Older age with smoking history and less reversibility
• C. Rapid progression with constant symptoms
• D. Fever and productive cough

Answer: (A)

The feature that best distinguishes asthma from COPD in a dyspneic patient is a history consistent with onset in childhood, episodic symptoms that vary with triggers, and atopy, paired with airflow obstruction that is reversible after bronchodilators. Asthma reflects bronchial hyperreactivity and inflammatory changes that respond well to bronchodilators or anti-inflammatory therapy, so lung function tests often show a noticeable improvement after a bronchodilator challenge (for example, a significant rise in FEV1). In contrast, COPD usually emerges later in life, often after many years of smoking, with a gradual, persistent course and airflow limitation that is less reversible with bronchodilators. Fever and productive cough point to infection or another acute process rather than the typical chronic, reversible pattern of asthma, and rapid progression with constant symptoms is more aligned with COPD than with asthma.