[Dermatomyositis--pathogenesis, diagnosis, therapy]

Dermatomyositis is a rare systemic autoimmune disease that principally involves the skeletal muscles. Currently, the etiopathology is suspected to involve a viral infection with underlying genetic susceptibility, resulting in an abnormal immune reaction. Autoantibodies, in particular against enzymes involved in protein synthesis--especially aminoacyl-tRNA synthetases--appear to be found for the most part when the lungs are involved. Differential diagnosis is facilitated by the detection of various auto-antibodies. Treatment is unsatisfactory, and controlled studies, in particular when resistance to prednisone presents, are lacking. The prognosis depends, among other things, on the internal organs involved (heart, lungs, gastrointestinal tract, endocrine system). The search for viruses (e.g. hepatitis B) should be intensified using the latest, more sensitive, methods.