Scleroderma is a rare autoimmune connective tissue disorder characterized by abnormal hardening of the skin and, sometimes, other organs. It is classified into two main forms: localized scleroderma and systemic sclerosis (SSc), the latter comprising three subsets; diffuse cutaneous SSc (dcSSc), limited cutaneous SSc (lcSSc) and limited SSc (lSSc) (see these terms).