Juvenile dermatomyositis

Juvenile dermatomyositis (JDM) is a rare but important autoimmune paediatric disease. The main clinical features are proximal muscle weakness and skin rashes or other skin manifestations, but multiple organ systems can also be involved. Diagnosis is made using the 1975 Bohan and Peter diagnostic criteria (a gold standard for clinical trials) or by revised criteria from 2006 based on an international consensus survey process. Optimal treatment requires a multidisciplinary approach, and is based on immunosuppression combined with intensive physiotherapy. Initially medical treatment involves intravenous and oral corticosteroids with adjuvant disease modifying anti-rheumatic drugs (DMARDs) and later biologic therapy. Randomised controlled trials are limited due to the low incidence but consensus on treatment has been agreed and is shown in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) protocol. Without treatment, mortality can be high but with early diagnosis and treatment the prognosis is good, with a third achieving full remission, a third having a cyclic, relapsing and remitting course and the remainder having an ulcerative chronic course.