Which finding on history and physical exam is most characteristic of asthma?

• A. Shortness of breath only during exertion
• B. Wheezing with prolonged expiratory phase; cough worse at night; improves with bronchodilators
• C. Recurrent pleural rub
• D. Chest pain worse with inspiration

Answer: (B)

Asthma presents as episodic, reversible bronchoconstriction from airway hyperresponsiveness. The most characteristic history features are wheezing with a prolonged expiratory phase, a cough that worsens at night, and improvement with bronchodilators. The expiratory wheeze reflects narrowed airways during exhalation, the nocturnal cough reflects circadian variation in airway inflammation, and responsiveness to bronchodilators shows reversibility of the obstruction. Shortness of breath only with exertion lacks this typical nocturnal, episodic pattern and reversibility. Recurrent pleural rub or chest pain worse with inspiration points to pleural disease, not asthma.