A noteworthy group of maladies of unknown origin which primarily involve connective tissue has been termed collagen diseases. These include the conditions known as periarteritis nodosa or polyarteritis, dermatomyositis, scleroderma, and disseminated lupus erythematosus. There are, indeed, several other diseases, such as rheumatoid arthritis, rheumatic fever, and serum sickness, which exhibit structural changes in collagen but of a somewhat limited scope. These can be distinguished from the group of diffuse alterations of collagen under present consideration.
For the purpose of orientation I will very briefly outline the general pathology of these afflictions.
Periarteritis nodosa: widespread focal necrosis and obliteration of the walls of the medium- and small-sized arteries.
Dermatomyositis: chronic nonsuppurative inflammation of the skin and muscles.
Scleroderma: thickening of collagen fibers throughout the body, especially in the skin.
Disseminated lupus erythematosus: degenerative changes in connective tissue of the vascular system, also in serous and synovial membranes.
Similar but nonspecific
CONSTANTINE FH. General Manifestations and Symptoms of Collagen Diseases. AMA Arch Ophthalmol. 1956;56(4):544-547. doi:10.1001/archopht.1956.00930040552002