Idiopathic inflammatory myopathies are a group of autoimmune diseases characterized by proximal muscle weakness and inflammation of skeletal muscle. Specific forms of idiopathic inflammatory myopathy include polymyositis, dermatomyositis, and inclusion body myositis. Inflammatory myopathies have a bimodal distribution, occurring in patients between 10 and 15 years and 45 and 60 years of age, ex...
