[Classic/amyopathic dermatomyositis]

Dermatomyositis (DM) is an inflammatory myopathy characterized by a typical cutaneous rash and proximal weakness. DM results from endothelium deposition of the complement membranolytic attack complex C5b-9, followed by inflammation. It is thus possible to have cases of DM with the typical rash, but with no associated myositis--amiopathic DM. DM represents a higher risk of association with malignancy and sometimes behaves as a paraneoplastic syndrome. As DM can be the alarm sign, once diagnosed, exclusion of malignancy should be done. In this article we also discuss the treatment and prognosis of dermatomyositis, according to the literature.