Calciphylaxis is a disease in which blood vessels (veins and arteries) become blocked by a build-up of calcium in the walls of the vessels, preventing blood from flowing to the skin or internal organs. The lack of blood flow (ischemia) damages healthy tissue and may causes the tissue to die (necrosis). The most obvious and frequent symptom of Calciphylaxis is damage to the skin, as ulcers can develop and become infected easily. Calciphylaxis can also affect fat tissue, internal organs, and skeletal muscle, causing infections, pain, and organ failure. The exact cause of Calciphylaxis is unknown.