[Treatment of Dermatomyositis and Immune-Mediated Necrotizing Myopathy with Poor Muscle Recovery with Steroids and IVIg: Intractable Dermatomyositis and Immune-Mediated Necrotizing Myopathy].

Among idiopathic inflammatory myopathies, dermatomyositis and immune-mediated necrotizing myopathy are distinguished by their different clinicopathological features. Corticosteroids are administered as the first-line treatment for both, and immunosuppressive agents and intravenous immunoglobulin important second-line treatments. Since some patients show resistance to these therapies, it is necessary to considering additional treatment based on muscle pathology, muscle imaging, and systemic complications such as malignancy and interstitial lung disease, in addition to the careful evaluation of muscle strength. However, more effective therapeutic strategies are not yet well-established for refractory cases because the available therapeutic agents are limited. Therefore, the development of novel therapies is required in the future.