Amyopathic dermatomyositis (dermatomyositis siné myositis). Presentation of six new cases and review of the literature.

We report six patients with the classic cutaneous findings of dermatomyositis who did not develop clinical or laboratory evidence of muscle disease for at least 2 years after onset of their skin manifestations. Such patients represent 11% of our total experience with dermatomyositis patients during a 15 year period. All six patients had Gottron's paules, periungual erythema/telangiectasia, and violaceous discoloration of the face, neck, upper chest, and back at some time during the course of their disease. In addition, all complained of pruritus and photosensitivity. None of the patients had evidence of malignancy. Each of five patients treated with oral corticosteroids for their cutaneous disease had marked improvement and did not develop myositis. These cases further emphasize that the cutaneous manifestations of dermatomyositis are pathognomonic of this disease and challenge the commonly held notion that muscle disease always develops within 2 years of onset of skin disease.