It’s taken 2 years for family members to convince this 50-year-old black woman to consult dermatology about dark circles on her arms and trunk. The asymptomatic lesions were only faintly discolored at manifestation but have darkened with each recurrence. The 6 lesions she currently has are in the exact locations they originally manifested in.
Convinced she had “ringworm,” the patient tried several different antifungal creams, to no avail. Then her primary care provider prescribed a 2-month course of oral antifungal medication (terbinafine)—again, with no change to the lesions.
The patient is otherwise healthy except for osteoarthritis, for which she takes ibuprofen (800 mg 2 or 3 times a day). She denies any history of seizure, chronic urinary tract infection, or other chronic infection.
EXAMINATION
The 6 perfectly round, uniformly pigmented, dark brown macular lesions on the patient’s arms and trunk range from 2 to 5 cm in diameter. A faint, rusty brown halo can be seen around the periphery of the lesions, giving them a targetoid look. The surfaces of the lesions are completely smooth.
What’s the diagnosis?