Juvenile dermatomyositis (JDM) is a disease in children that causes skin rash (dermato) and muscle inflammation (myositis) resulting in weak muscles.
JDM is a type of autoimmune disease. The immune system is a group of cells that functions to protect the body from infections. In autoimmune diseases like JDM, these cells fight the body's own tissues and cells, resulting in inflammation and tissue damage.
JDM is different from adult dermatomyositis. In JDM, there is no increased risk of cancer. However, blood vessel involvement is frequent and often severe. Also, calcium deposits (calcinosis) are common, especially in the recovery phase.