Diagnosis and assessment of the collagen diseases.

Polyarthritis is a characteristic feature of the collagen diseases which include rheumatoid arthritis, systemic lupus erythematosus, scleroderma, polymyositis, Sjögren's syndrome and polyarteritis. However, the connective tissues of many different organs other than joints may be affected in these disorders. For example, many workers believe that rheumatoid arthritis should be called rheumatoid disease. The important shared and distinguishing features of each of the collagen diseases are described. The manifestations of the collagen diseases have been found to be associated with vasculitis, lymphocytic infiltration of tissues and the presence of auto-antibodies. Implications of these findings for the management of patients suffering from the collagen diseases are outlined.