Question

A 45-year-old woman comes to the outpatient continuity clinic with a 4-month history of episodic shortness of breath, low-grade fever, chills, and a dry cough. She reports that her symptoms typically begin on Saturday evenings, persist through Sunday, and gradually resolve by Tuesday. Her past medical history is significant for gastroesophageal reflux disease (GERD) and allergic rhinitis. Her current medications are omeprazole and as-needed cetirizine. She is a lifelong non-smoker and works Monday through Friday as an accountant in a corporate office. Vital signs are temperature 37.8°C (100.0°F), pulse 92/min, respirations 18/min, and blood pressure 128/82 mmHg. Pulse oximetry shows 94% on room air. Lung auscultation reveals bilateral fine crackles without wheezing. Laboratory studies show a mild peripheral eosinophilia of 6% (normal: 1-5%). A recent trial of an albuterol inhaler prescribed at an urgent care clinic provided no symptom relief. Which of the following areas of medical history is most critical to investigate next to establish the correct diagnosis?