The relationship of allergy to the collagen diseases

The collagen diseases appear to be a varied group of abnormal states showing no evidence of a common pathogenesis, although several appear to exhibit immunologic features. Even the various types of polyarteritides appear to involve several different mechanisms. In general, more detailed immunologic investigations of the various collagen diseases tend to bring out differences rather than similarities. The only diseases of the group in which specific causative agents have been found are rheumatic fever and certain cases of hypersensitivity angiitis. Autosensitization appears to be a probable pathogenetic factor in lupus erythematosus, and possibly in rheumatoid arthritis, but the immunologic mechanisms of both are only partially understood. The term “collagen disease” appears to have outlived its usefulness as a pathogenetic classification. The etiology of each disease of the group must be considered separately.