Hi, Lula - I have had calcinosis on the fingers of both hands for about 4 years and I have a couple on the outside wrist bones too. They look like little white lumps under the skin. They are more annoying than painful, although one on my left ring finger is right on the knuckle, so that finger is stiff and I can't wear rings - too painful. They are very common in the CREST form of scleroderma, but many people with myositis have them too, and they can also occur in SLE, although they are rare in SLE. They can also be caused by vitamin d excess, and by other metabolic and endocrine problems that affect how your body processes calcium. So these deposits of calcium salts end up under the skin. These calcifications can affect internal organs but that is uncommon and usually occurs with other diseases. The hardening of the skin and organs that occurs with scleroderma is caused by fibrosis, not calcification, so it's a different process.
There is not really any treatment for calcinosis, other than surgical removal if you have one that is painful or large. You might also get them on you knees or elbows although I never have. Managing the underlying disease is the best treatment. These nodes don't have anything to do with too much calcium in your diet, so don't worry about trying to restrict calcium.
A couple of things you do need to be careful about -if you have any nodes on your fingertips, you might get ulcers on your fingertips because the calcium deposits damage the blood vessels and impair the circulation to your fingertips. Any of the nodes can become ulcerated because the skin over them is fragile, and the underlying blood vessels may be damaged, but the fingertips seem to be the most prone to this. So protecting your hands is important, and let your doctor know if any of the nodes start to get inflammed and ulcerated looking. Because the skin is so fragile, it can sometimes break open, and you might notice some white, chalky looking oozing - this is common and doesn't mean there's a problem - just keep any open areas clean and bandaged and use an antibiotic ointment to prevent infection, and they should heal back up.
Hope this helps!