A man presents with a lifelong history of asymptomatic irregular pale patches on his shoulder and back. What is the diagnosis?
A 32-year-old man had a lifelong history of a series of asymptomatic, irregular, pale patches concentrated on his left upper shoulder and back. There was no associated scaling, and the surrounding skin had a pink blush. Stroking of the skin failed to elicit dermographism or a flare within the pale patches. No skin biopsy was obtained.