[Skin changes in paraproteinemias (monoclonal gammopathies)]

Numerous skin disorders or skin lesions are associated with a monoclonal gammopathy (formerly: paraproteinemia). These skin diseases can be differentiated in the following way: specific skin lesions caused by monoclonal immunoglobulin producing cells in the skin, in generalized plasmocytoma or morbus Waldenström. In another group of disorders the monoclonal immunoglobulins induce functional disturbances, e.g. Raynaud syndrome (if the monoclonal immunoglobulins are cryoglobulins), xanthomatosis through interactions between these immunoglobulins and lipoproteins, purpura in immunoglobulin induced stasis and hyperviscosity. The unlimited spreading of the plasmocytoma cells replaces normal immunoglobulin producing plasma cells followed by a disturbance of the humoral immune response, which is frequently accompanied by atypical infections of skin or other organs. Furthermore, an almost obligatory association with monoclonal gammopathies has been demonstrated in a few skin diseases, e.g. scleromyxedema. However, the role of the immunoglobulins in these disorders is unknown. In some other skin diseases, such as pyoderma gangrenosum, acrodermatitis atrophicans Herxheimer, scleredema Buschke etc., a monoclonal gammopathy is only detectable in some patients.