Calcinosis cutis is the accumulation of calcium salt crystals in your skin. The calcium deposits are hard bumps that don't dissolve. The shape and size of the lesions vary. This is a rare condition that has many different causes. These range from infection and injury to systemic diseases like kidney failure. For smaller lesions, drugs that may help include: warfarin, ceftriaxone, intravenous immunoglobulin (IVIG) For larger lesions, drugs that may help include: diltiazem, bisphosphonates, probenecid, aluminum hydroxide