Progress in diagnosis and treatment of dermatomyositis

Dermatomyositis (DM) is characterized by skin lesions, skeletal muscle inflammation, and involvement of other organs. The pathogenesis of DM includes susceptibility genes, environmental stressors, immune and non⁃immune inducing mechanisms. DM usually presents as subacute progressive proximal muscle weakness, skin rash, or both. Other common extramuscular findings include various heart abnormalities, interstitial lung disease (ILD), and malignant tumors. The auxiliary examination of DM includes the examination of myositis autoantibodies, myoenzymes and electromyography (EMG). Skin treatments for DM include photosensitivity inhibition drugs and antimalarial drugs. If the DM is associated with muscle involvement, systemic corticosteroids is the first line of treatment, and immunosuppressants are used for refractory diseases or as corticosteroids sparing agents in the event of side effects. Other treatments include oral calcineurin inhibitors, cyclophosphamide, biologic agents and Janus kinase (JAK) inhibitor.