Definition

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. The most significant differences between JDMS and adult dermatomyositis are as follows:

• Children are more likely than adults to develop calcinosis (calcium deposits in the skin) and gastrointestinal symptoms.
• Children are more likely to develop...