DERMATOMYOSITIS IS a chronic inflammatory disorder involving skin and muscle; it may, in certain instances, be associated with pulmonary manifestations, cardiac involvement, and/or malignancy. It is commonly understood in this disorder, as in others, that not all manifestations need occur simultaneously, nor with the same degree of severity. In addition, some manifestations may be absent or have only minimal expression. In the case of its central features, however, controversy has arisen over incomplete disease presentation. Without rash, most authorities currently believe that the disease mechanisms and immunologic profile of polymyositis are so unique that this disorder should be set apart as a distinct nosologic entity.
This suggestion largely rests on the character of the inflammatory infiltrate in muscle, as well as on certain clinical findings. Biopsy findings in dermatomyositis demonstrate the presence of an inflammatory infiltrate characterized by a T-lymphocytic response containing both See also page 1381 CD4 and CD8