Localized scleroderma is characterized by thickening of the skin from excessive collagen deposits. Collagen is a protein normally present in our skin that provides structural support. However, when too much collagen is made, the skin becomes stiff and hard. Localized types of scleroderma are those limited to the skin and related tissues and, in some cases, the muscle below. Internal organs are not affected by localized scleroderma, and localized scleroderma can never progress to the systemic form of the disease. Often, localized conditions improve or go away on their own over time, but the skin changes and damage that occur when the disease is active can be permanent. For some people, localized scleroderma is serious and disabling.
There are two generally recognized types of localized scleroderma: morphea and linear.
Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.