Juvenile onset idiopathic inflammatory myopathy (IIM) has many similarities and distinct differences from adult-onset disease. This review will focus on recent developments in understanding and treatment of juvenile dermatomyositis (JDM), the most common disease sub-type of IIM in childhood. JDM is a systemic immune mediated vasculopathy, increasingly recognised as a group of distinct phenotypes with variable presentation and outlook. This overview will describe long-term outlook and disease course including health-related quality of life and emerging treatments.