Clinical Challenge: Abrupt Onset of Hair Loss

The patient is a 63-year-old Hispanic woman who complains of the abrupt onset of hair loss, first noted 6 weeks ago. Baseline laboratory studies ordered by her internist, including complete blood count, thyroid-stimulating hormone, serum iron, and antinuclear antibody panel, were unremarkable. Relevant medical history includes cardiac surgery performed 6 months ago. She is currently on multiple medications, including a ...