Anti‐MDA‐5‐positive amyopathic dermatomyositis with cutaneous ulcerations

A 78‐year‐old woman presented with a recurrent painful ulcerating rash on her hands. She had cutaneous ulcerations over Gottron papules on the first metacarpophalangeal joints of both hands (Figure, A) and a tender rash over the palmar surface with ulcerations of the skin over the fingertips (Figure, B). Motor power was preserved and creatine kinase and aldolase levels were normal. Tests for anti‐melanoma differentiation‐associated protein 5 (MDA‐5) and anti‐Ro‐52 autoantibodies returned positive and she was diagnosed with anti‐MDA‐5‐positive amyopathic dermatomyositis.

Differential diagnoses for ulcerating lesions of the hands include pyoderma gangrenosum, cholesterol emboli and neutrophilic dermatoses. Amyopathic dermatomyositis presents with classic cutaneous features but without clinical evidence of muscle disease;1 therefore, a complete myositis screen should still be performed even when muscle enzyme levels are normal.