Dermatomyositis is a connective tissue disease where for the most part inflammatory and degenerative changes commonly occur in the affected muscles and skin.
By and large, it is an autoimmune disease, although surprisingly the precise mechanism of it is unknown. But what certainly is known is that cell mediated immune cells play a role in the infiltration and inflammation of muscles and skin.
To clarify, there also seems a cross reaction between certain tumors, autoimmune antibodies and the muscle antigens. In fact, there may be a shared antigen that makes dermatomyositis occur comparatively more often alongside certain tumors.
In general, approximately 15% of men and less women with dermatomyositis have a hidden malignancy in their bodies. Uniquely, dermatomyositis is more common in women than in men with a ratio of 2 to 1. In general, sometimes a viral infection can be followed by the development of dermatomyositis. Specifically, picorna viruses have been implicated in a number of dermatomyositis cases. Notably, there are two age group peaks, the first one in childhood from age 5 to 15 and secondly, another peak at age 40 to 60 (Ref. 1).
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