Calcium Deposit
It is also called calcinosis. With a prolonged course of scleroderma, calcification (calcium deposits in the skin and subcutaneous structures) is often observed, which is localized mainly in the area of the hands, forearms, elbow, and knee joints.
The deposition of calcium is in the connective tissues that are beneath your skin. Underneath your skin, you can feel 1 or more hard, painful lumps. It can be quite painful if a calcium deposit breaks through the skin. When this happens, a white or chalky substance will appear on your skin. You may develop an infection and painful open sore.