A 55-year-old woman presents for evaluation of a widespread rash that first appeared several months ago. The rash has resisted treatment with various OTC products—antifungal cream (tolnaftate), triple-antibiotic cream, and tea tree oil—and continues to itch terribly at times.
Her primary care provider prescribed oral terbinafine (250 mg/d) for a proposed fungal etiology after viewing the rash with a Wood lamp and performing a KOH prep. A one-month course yielded no relief.
The patient claims to be in good health otherwise. She does admit to going through a stressful period involving job loss, divorce, and care of her aging parents.
Multiple papulosquamous papules, nodules, and plaques are located on the patient’s arms, legs, wrists, and sacrum. The lesions range from pinpoint to several centimeters and oval to polygonal. They have a striking purple appearance. On closer inspection, many have a shiny, whitish sheen on the surface.
What is the diagnosis?