Juvenile dermatomyositis (JDM) is a systemic, autoimmune inflammatory muscle disorder and vasculopathy that affects children younger than 18 years. JDM primarily affects the skin and the skeletal muscles.
Characteristic findings include Gottron’s papules, a heliotrope rash, calcinosis cutis, and symmetrical, proximal muscle weakness.
Juvenile Myositis (JM), including Juvenile Dermatomyositis (JDM) and Juvenile Polymyositis (JPM), are rare autoimmune conditions which cause inflammation. The inflammation for JPM primarily occurs in the muscles, while in JDM the inflammation is in the blood vessels that lie under the skin and in the muscle tissue. This inflammation causes weak muscles and – in the case of JDM – skin rashes. If blood vessels or muscle cells in other parts of the body are inflamed, other systems of the body can be affected, such as the digestive tract, heart, and lungs. The condition itself and the treatment for the disease can be life-threatening.