A 42-year-old man presents to the clinic with progressive shortness of breath on exertion over the past 2 years and a new, painful skin rash. He reports a chronic cough and occasional wheezing. He quit smoking 5 years ago, having accumulated a 15 pack-year history. One week ago, he developed tender, red nodules on his buttocks and thighs, which have recently begun discharging an oily yellow fluid. A recent routine wellness check noted mildly elevated transaminases. His family history is significant for a father who died of "liver and lung trouble" in his 50s. He is a thin man breathing comfortably at rest. His blood pressure is 128/82 mmHg, heart rate is 88 bpm, respiratory rate is 18 breaths per minute, and temperature is 98.4 F.