Tissue necrosis caused by distal capillary thrombosis resulting from cryoglobulin precipitation in the vessels. The black tissue under the nails is ischemic, and will eventually slough, or be reabsorbed by the body.
Update Date 1/24/2011
Updated by: Todd Gersten, M.D., Hematology/Oncology, Palm Beach Cancer Institute, West Palm Beach, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.