5. Diffuse scleroderma: More areas of the skin are involved and thickened, but there is a high degree of variability among patients. Skin of the arms, legs, and trunk are more likely to be involved. It has a higher risk of developing “sclerosis” or fibrous hardening of the internal organs. In this case, skin thickening occurs more rapidly and involves more skin areas than in the limited form of the disease.