Dermatomysitis (DM), Polymyosistis (PM), and Inclusion-Body Myositis (
IBM) are the three major inflammatory myopathies (IM) (Dalakas, 1991;
Karpati et Carpenter, 1993; Engel et al,, 1994; Hohlfeld et Engel, 199
4). We will provide an update on the clinical characteristics, diagnos
tic criteria, and pathogenetic mechanisms that separate each one of th
ese myopathies and discuss the current approach to treatment.