As nouns the difference between scleroderma and lupus

is that scleroderma is a chronic disease characterized by excessive deposits of collagen in the skin or other organs while lupus is any of a number of autoimmune diseases, the most common of which is systemic lupus erythematosus.

As a proper noun Lupus is

a summer constellation of the northern sky, said to resemble a wolf. It lies south of the constellation Libra.