Scleroderma - Prognosis

Diagnosis

There are no specific tests for scleroderma. The doctor may suspect scleroderma after taking a history of the symptoms and performing a physical examination. As part of this examination, the doctor does the following:

• Checks the skin for thickened and hardened areas. The major signs of scleroderma are hardening and thickening of the skin in any areas on the fingers and toes.
• Presses affected tendons and joints to detect crackling or grating sensations, which can indicate changes related to scleroderma beneath the skin.
• Examines the fingernails underneath a microscope. The doctor may find changes in capillaries that are characteristic of scleroderma or mixed connective tissue disease.

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Tests for Antinuclear Antibodies

Tests may be done to detect immune factors called antinuclear antibodies (ANAs). Detecting specific types of ANAs may help diagnose scleroderma. ANA subtypes include the following:

• Rheumatoid factor, anti-single-stranded DNA, and antihistone antibodies are autoantibodies associated with scleroderma, but they are also common in other autoimmune disorders, such as rheumatoid arthritis and systemic lupus erythematosus. Some ANAs attack RNA or DNA, the genetic material in cells.
• Anti-RNA polymerase III, anti-topoisomerase I (also called anti-DNA topo 1) and anti-centromere antibodies (ACA) are also autoantibodies. Most patients with systemic scleroderma (but not localized scleroderma) have one or more of these autoantibodies. They do not appear at the same time, and seem related to different phases of the disease process. For example, anti-DNA topo 1 often occurs with diffuse skin scleroderma and lung complications. Anti-centromere antibodies usually occur with a less severe form of the disease.
• Higher-than-normal levels of autoantibodies to fibrillin 1, a protein found in muscle and other connective tissues, is more common in patients with both systemic and localized scleroderma. This autoantibody in localized scleroderma is more common in some ethnic groups (such as Japanese and Native Americans) than in others (Caucasians). It is not found in other autoimmune diseases.