Dermatomyositis is a connective tissue disease where inflammatory and degenerative changes are commonly found in the affected muscles and skin.
It is an autoimmune disease, although the precise mechanism is unknown. What is known is that cell mediated immune cells play a role in the infiltration and inflammation of muscles and skin.
Also, there seems a cross reaction between certain tumors and autoimmune antibodies and the muscle antigens.There may be a shared antigen that makes dermatomyositis occur more often alongside certain tumors.
Approximately 15% of men and less women with dermatomyositis have a hidden malignancy in their bodies. Dermatomyositis is more common in women than men with a ratio of 2 to 1. Sometimes a viral infection can be followed by the development of dermatomyositis. Picorna viruses have been implicated in a number of dermatomyositis cases. There are two age group peaks, one in childhood from age 5 to 15 and another peak at age 40 to 60 (Ref. 1).
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