Juvenile Dermatomyositis (JDM) is a rare disease but the most common idiopathic inflammatory myopathy (IIM) of childhood. It is a systemic vasculopathy primarily affecting the skin and muscles, causing classic signs of rash and proximal muscle weakness but can present with heterogeneous features, natural history and outcomes. This chapter highlights the differences in clinical presentation between paediatric and adult phenotypes and presents an update of treatment strategies during adolescence and young adulthood, with focus on disease outcomes, including cardiovascular involvement, reproductive health and vocational developmental milestones.