Essential mixed cryoglobulinemia
When more than one type of immunoglobulin component is present (types II and III cryoglobulinemia), the term mixed cryoglobulinemia is used. Mixed cryoglobulinemia is often caused by infection with hepatitis C virus (HCV) and less commonly with hepatitis B virus (HBV), an underlying autoimmune condition (such as systemic lupus erythematosus, rheumatoid arthritis, or Sjögren syndrome), or lymphoproliferative disease. In around half of cases, no underlying cause is found; this is termed essential mixed cryoglobulinemia.
The pathogenesis of essential mixed cryoglobulinemia involves deposition of the mixed cryoglobulin-antigen complexes in small vessels, causing vasculitis and possible resultant end-organ damage.
Patients may complain of muscle aches or weakness, fevers, unexplained weight loss, joint pain, or skin changes that worsen when exposed to the cold. Cutaneous findings include palpable purpura, retiform purpura, dermal nodules, livedo reticularis, digital necrosis, and Raynaud phenomenon. Extracutaneous involvement includes arthralgias and rare arthritis, glomerulonephritis, peripheral neuropathy, and interstitial lung infiltrates.
D89.1 – Cryoglobulinemia
239947001 – Essential mixed cryoglobulinemia
Differential Diagnosis & Pitfalls