Dermatomyositis (DM) is an inflammatory myopathy of skeletal muscle with characteristic cutaneous findings. It is a rare disorder with a bimodal age distribution that affects almost twice as many women as men. One category of DM, normal-enzyme DM, is characterized by cutaneous changes only at baseline, normal serum muscle enzyme levels and myositis demonstrated by electromyography (EMG) and/or muscle biopsy specimens. Typically, patients with normal-enzyme DM progress to severe muscle involvement and require systemic corticosteroid therapy. The patient we report has normal-enzyme DM confirmed by serial serum enzymes, EMG, and skin and muscle biopsies but is unique in that she never experienced progression of muscle weakness although muscle involvement was documented histologically and by EMG. Follow-up examination after 1 year revealed near-complete resolution of cutaneous involvement after topical therapy and no evidence of muscle weakness.
