Description: This episode provides a detailed exploration of the clinical manifestations, diagnosis, and differential diagnoses of dermatomyositis (DM) and polymyositis (PM), two immune-mediated myopathies, as outlined in the UpToDate articles. It covers the hallmark features of muscle weakness and inflammation, with a focus on DM’s distinctive skin manifestations and the variant clinically amyopathic DM (CADM). The podcast delves into epidemiology, key clinical signs, laboratory findings, and diagnostic approaches, including the role of imaging and muscle biopsies to distinguish DM and PM from conditions like inclusion body myositis (IBM) and immune-mediated necrotizing myopathy (IMNM). Grounded in UpToDate’s comprehensive insights, each subtopic wraps up with a practical takeaway, highlighted by "if you can’t remember everything, remember this," to support residents in mastering these complex conditions.