what is jdm disease
Juvenile dermatomyositis (JDM) is an inflammatory disease that causes muscle weakness and a skin rash on the eyelids and knuckles.It affects an estimated 3,000-5,000 children in the United States. All age and ethnic groups are affected.uvenile dermatomyositis (JDM) is an inflammatory disease that causes muscle weakness and a skin rash on the eyelids and knuckles.