Polymyositis and Dermatomyositis

Polymyositis is a progressive inflammatory myopathy that involves chronic muscle inflammation accompanied by muscle weakness on both sides of the body. It affects the skeletal muscles of the body that are involved in movement.
Dermatomyositis is another inflammatory myopathy disease, similar to polymyositis, which is associated with skin rashes or other skin changes.
While both conditions affect women more than men, polymyositis occurs within the age group of 30 to 50 years, and dermatomyositis, at the age of 5 to 15 and 40 to 60.