Systemic Sclerosis Diagnosis and Management

Initial Screening and Diagnosis

The American College of Rheumatology recommends all patients with suspected systemic sclerosis should undergo antinuclear antibody (ANA) testing by indirect immunofluorescence as the initial screening test, followed by specific autoantibody profiling to identify disease-specific antibodies that predict organ involvement and prognosis 1
The pattern observed in ANA testing (homogeneous, speckled, nucleolar, centromere) provides initial clues to specific autoantibody types, according to the European League Against Rheumatism 2
Complete blood count, glucose, electrolytes, kidney function, and liver enzymes should be obtained in all patients, as recommended by the American College of Rheumatology 1

The American College of Rheumatology recommends testing for anti-topoisomerase I (anti-Scl-70), which is strongly associated with diffuse cutaneous systemic sclerosis, interstitial lung disease, and digital ulcers, and predicts poor prognosis 1
Anti-RNA polymerase III (anti-RNAP III) is associated with diffuse cutaneous disease, rapid skin progression, scleroderma renal crisis, and increased malignancy risk, according to the European League Against Rheumatism 1
Anti-U1RNP antibodies suggest mixed connective tissue disease or systemic sclerosis overlap syndrome, as recommended by the American College of Rheumatology 1 and the European League Against Rheumatism 2

Pulmonary function tests, including forced vital capacity and diffusing capacity for carbon monoxide, should be performed at baseline and regularly, especially in early diffuse cutaneous systemic sclerosis and anti-Scl-70 positive patients, according to the American Thoracic Society 1
High-resolution CT of the chest should be used to screen for interstitial lung disease, particularly in high-risk patients, as recommended by the European Respiratory Society 3
N-terminal pro-B-type natriuretic peptide should be tested if arrhythmias or heart failure are present, according to the American Heart Association 1

Repeat pulmonary function tests every 3-6 months in early disease or if interstitial lung disease is present to detect progression, as recommended by the American Thoracic Society 3
Annual urinalysis for proteinuria should be performed starting at age 10 years or earlier if renal involvement is suspected, according to the American College of Rheumatology 1
Monitor complete blood count and liver enzymes if on immunosuppressive therapy, as recommended by the European League Against Rheumatism 1
Anti-RNAP III positivity warrants age-appropriate malignancy screening within 3 years of systemic sclerosis diagnosis due to increased cancer risk, according to the American College of Rheumatology 1