Dermatomyositis is one of a group of relatively uncommon diseases known as inflammatory myopathies, or inflammatory disorders of the muscles.
Dermatomyositis is distinguished from other diseases in this category by the fact that it causes a characteristic skin rash as well as affecting the strength and functioning of the muscles.
Dermatomyositis in children and adolescents is called juvenile dermatomyositis (abbreviated JDMS or simply JD) because it is different from the adult form of the disorder in several respects.
Adults with dermatomyositis over the age of 50 have a 15 percent risk of developing cancer, whereas juvenile dermatomyositis is rarely associated with malignancy.
The third major symptom of juvenile dermatomyositis is a low-grade fever (one or two degrees Fahrenheit above normal).