The collagen diseases.

The collagen diseases have in common certain relatively specific alterations in the tissues that are derived from the mesenchyme.In reviewing the development of this concept, the nature and the pathogenesis of these changes and the blocking effect of cortisone and ACTH are discussed. The term "diseases of the collagen system" includes a number of clinical states within a broad spectrum of variation in the basic alterations of collagenous and vascular tissues. In rheumatoid arthritis the modifications are chiefly in the somatic connective tissue; in periarteritis nodosa the blood vessel involvement is preeminent; dermatomyositis and disseminated lupus erythematosus present more intermediate mixtures of these changes.