Myositis

Idiopathic inflammatory myositis especially dermatomyositis and polymyositis are systemic autoimmune diseases with significant mortality and morbidity. Muscle weakness of the proximal muscles is the most common presenting clinical feature. Since idiopathic inflammatory myositis are relatively uncommon, randomised control trials are scarce. Therefore evidence-based optimal treatment regime has not been defined. Corticosteroids are first line treatment but many patients will require further immunosuppressive or immunomodulatory treatment. Methotrexate, azathioprine and ciclosporin are amongst the mostly common used second line agents although their benefit have not been adequate studied in randomised control trials. In dermatomyositis, one randomised control trial showed that intravenous immunoglobulin is efficacious. More recently tumour necrosis factor antagonists and rituximab, a monoclonal antibody that deplete B cells have shown therapeutic promise in case series.