THE MERCK MANUAL: The Merck Manual of Diagnosis and Therapymultimedia


  • Dysproteinemias Causing Vascular Purpura
  • Cryoglobulinemia

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    Cryoglobulins (cold-precipitable proteins in serum) may be idiopathic or related to an underlying lymphoproliferative syndrome or plasma cell dyscrasia. Cryoglobulins may be IgG, IgM, or IgA. Mixed cryoglobulins are usually composed of rheumatoid factor IgM complexed with a monoclonal or polyclonal IgG. Cryoglobulinemia may be idiopathic or secondary to a disorder such as hepatitis C infection. The immune complexes can interfere with normal platelet function and fibrin polymerization. Hyperviscosity and direct vascular trauma due to circulating cryoglobulins cause small-vessel hemorrhage. Cryoglobulinemia can manifest with acral hemorrhagic necrosis, palpable purpura, livedo reticularis, and frank leg ulcerations.

    By permission of the publisher. From Deitcher S. In Atlas of Clinical Hematology. Edited by JO Armitage. Philadelphia, Current Medicine, 2004.