Scleroderma is a chronic autoimmune disease where the immune system mistakenly attacks healthy body tissue. This leads to an overproduction of collagen, causing thickening and hardening of the skin and potentially affecting internal organs. Early and accurate diagnosis is important because scleroderma presents differently among individuals and can impact multiple organ systems. While there is no cure, timely diagnosis allows for managing symptoms and limiting disease progression.
Initial Medical Evaluation
The diagnostic process for scleroderma often begins with a thorough medical evaluation. A doctor will ask about the patient’s medical history, focusing on specific symptoms. These include skin changes like thickening or tightness, color changes in fingers or toes when exposed to cold or stress (Raynaud’s phenomenon), and joint pain or stiffness.
A physical examination is then conducted to identify characteristic signs of the disease. The doctor will examine the skin for areas of hardening, swelling, or unusual discoloration. They may also look for small, widened blood vessels (telangiectasias) or small white calcium deposits under the skin.
Blood Tests for Scleroderma
Blood tests are a significant component in diagnosing scleroderma, particularly the detection of specific autoantibodies. Antinuclear antibodies (ANA) are often the first tested, present in most scleroderma cases. While a positive ANA test suggests an autoimmune condition, it is not specific to scleroderma alone.
More specific antibodies help confirm a diagnosis and indicate the type of scleroderma. Anti-topoisomerase I (Scl-70) is associated with diffuse systemic scleroderma, affecting larger skin areas and internal organs. Anti-centromere antibodies (ACA) are found in limited systemic scleroderma, linked to skin changes primarily on the hands, face, and feet, and a higher risk of pulmonary hypertension.
Another antibody, anti-RNA polymerase III, is also associated with diffuse systemic scleroderma and can indicate a higher risk for kidney involvement. These specific autoantibodies provide insights into the disease’s progression and help categorize its form. Other general blood tests may assess inflammation or kidney and liver function, but the autoantibody profile is central to diagnosis.
Assessing Organ Involvement
Because scleroderma can affect various internal organs, evaluating their function is an important part of the diagnostic process. Pulmonary function tests (PFTs) assess lung capacity and airflow, as lung involvement like interstitial lung disease or pulmonary hypertension is common in systemic scleroderma. A high-resolution CT scan of the lungs may also visualize changes in lung tissue.
To check for heart involvement, an echocardiogram assesses the heart’s structure and function, and an electrocardiogram (EKG) detects abnormalities in heart rhythm. Kidney function is monitored through blood tests, such as creatinine levels, and urine tests to detect protein or blood, indicating kidney damage. Gastrointestinal issues, frequent in scleroderma, may involve motility studies to evaluate food movement or an endoscopy to examine the esophagus and stomach lining.
Imaging and Other Diagnostic Tools
Beyond blood tests and organ-specific assessments, other diagnostic tools provide additional information. Nailfold capillaroscopy examines the tiny blood vessels at the base of the fingernails under magnification. Characteristic changes in these capillaries, such as enlarged or distorted loops and capillary loss, indicate scleroderma and help differentiate it from primary Raynaud’s phenomenon.
Various imaging techniques are also used to detect internal changes. X-rays identify bone and joint abnormalities, though they are less specific for scleroderma itself. CT scans, especially high-resolution chest CTs, are used for detailed assessment of lung tissue and detecting early signs of interstitial lung disease. While less common for initial diagnosis, magnetic resonance imaging (MRI) may be used to assess muscle or joint inflammation.
Integrating Findings for Diagnosis
The diagnosis of scleroderma is a comprehensive process that integrates all gathered information. No single test confirms the disease; instead, doctors combine findings from the patient’s medical history, physical examination, and blood test results. The presence of specific autoantibodies, characteristic skin changes, and evidence of organ involvement are all weighed together.
Results from organ function tests and imaging studies contribute to the disease’s extent and subtype. This multi-faceted approach allows for accurate diagnosis and helps differentiate scleroderma from similar conditions.