Purpose of review: This article summarizes the clinical features, diagnostic evaluation, and management of the common immune-mediated myopathies: dermatomyositis, antisynthetase syndrome, immune-mediated necrotizing myopathy, and overlap myositis.
Recent findings: The identification of myositis-specific autoantibodies has improved the characterization of the subtypes of myositis and associated clinical phenotypes, as the severity of muscle involvement, extramuscular manifestations, and risk of malignancy may vary among the subtypes of autoimmune myopathies.
Summary: The understanding and diagnostic accuracy of the subtypes of autoimmune myopathies have been enhanced with careful attention to the key clinical features, the emergence of myositis-specific autoantibodies, the characterization of histopathologic hallmark features, and the aid of muscle imaging. Several immunotherapeutic options now exist that can be selected to target a specific subtype, often with a favorable prognosis, especially when treatment starts early in the disease course.