The skin thickening for which the disease is named is symmetrical on both sides of the body, usually beginning on the fingertips and moving up the arms. Legs and thighs also are affected. There is no way to predict if or when it will progress to diffuse scleroderma. Limited scleroderma occurs on the hands and possibly on the face and neck. Diffuse scleroderma is defined as skin tightening above the wrists or elbows.
More widespread disease can lead to severe organ damage.
The diagnosis of scleroderma is a clinical one based on symptoms rather than tests. However, skin or kidney biopsies can be done to look for signs of the disease, and other investigations can be carried out to evaluate the function of different organ systems. Blood tests commonly reveal certain antibodies, which may have informative value beyond simply confirming the diagnosis. The basic disease process is excessive production of collagen, the most abundant connective tissue fiber in the body. Many patients describe their path toward diagnosis as one of the most difficult periods of the illness, in part because the difficulty of the diagnosis can lead both physicians and patients to label the symptoms as psychosomatic, or caused by the mind.