Scleroderma is a connective tissue disease of unknown etiology. Its most characteristic feature is thickening of the skin due to increased collagen deposition. However, the disease may involve multiple other organ systems. Two broad categories of scleroderma have been defined: localized and systemic. Although all forms of scleroderma are rare, localized scleroderma occurs more frequently than systemic sclerosis and has a more favorable prognosis.
Several types of localized scleroderma exist. Morphea is characterized by the presence of one or more patches of hard, ivory-colored skin lesions. They begin with erythema and progress to nonpitting edema before becoming sclerotic. The margins of active lesions often have a violaceous hue. Underlying muscle fibrosis and atrophy may occur.