Collagen diseases in children.

Collagen disease is a pathological entity first established by Klemperer et al in 1942.1 The classical collagen diseases include rheumatic fever, rheumatoid arthritis, systemic lupus erythematosus, polyarteritis nodosa, dermatomyositis (polymyositis), and systemic scleroderma. These diseases are based on the widespread fibrinoid degeneration of collagen fibers occurring in the mesenchymal tissue. With the rapid progress in immunological research, collagen diseases are now accepted as a complex array of systemic autoimmune disorders that include over 40 diseases (Table 1). In this review, we focus on the characteristic clinical manifestations and laboratory findings of childhood patients with lupus erythematosus, dermatomyositis, and scleroderma, which are based on the Western literature plus cases and statistics from Japanese patients.