Derm Dx: An uncommon pruritic eruption

A 53-year-old nurse presents for evaluation of a minimally pruritic eruption affecting her arms and legs that has been present for 5 months. Family history is positive for sarcoidosis affecting her mother. The dermatitis has not responded to a course of prednisone or to topical therapy with clobetasol cream. No other family members are similarly affected. Examination reveals ...