Cutaneous changes of dermatomyositis precede muscle weakness.

A retrospective review of 50 patients with dermatomyositis was performed to determine the temporal relationship between onset of muscle weakness and skin involvement. We found that cutaneous changes sometimes preceded muscle weakness more than a year before the onset of muscle weakness. These findings suggest that the characteristic dermatomyositis eruption without muscle weakness should not preclude a diagnosis of dermatomyositis, and these cases should be carefully followed.