causes of juvenile arthritis
1 An inflammatory disease, juvenile dermatomyositis causes muscle weakness and a skin rash on the eyelids and knuckles. 2  Juvenile lupus. 3  Lupus is an autoimmune disease. 4  The most common form is systemic lupus erythematosus, or SLE. 5  Lupus can affect the joints, skin, kidneys, blood and other areas of the body.