Scleroderma is a complex, systemic autoimmune disease characterized by the overproduction of collagen, causing hardening and thickening of the skin and internal organs. Because symptoms overlap with other conditions, diagnosis is a multi-step process requiring the specialized knowledge of a rheumatologist. The diagnostic journey starts with a thorough physical assessment, followed by specific laboratory and imaging studies to identify the disease and determine its extent.
Initial Symptom Review and Physical Examination
The diagnostic process begins with a detailed review of the patient’s medical history and a physical assessment. The doctor asks about the onset of symptoms, such as Raynaud’s phenomenon, where fingers and toes turn white, blue, or red in response to cold or stress. Early clues also include unexplained joint pain, chronic fatigue, or persistent gastroesophageal reflux.
During the physical examination, the physician checks the skin for tightening and induration, the disease’s hallmark. They look for sclerodactyly—thickening and tightness of the skin on the fingers and toes, often causing a shiny appearance and loss of normal creases. Other visible signs include small, dilated blood vessels (telangiectasia) on the face and hands, and pitting scars or ulcers on the fingertips caused by poor circulation. Tracking the progression of skin changes is important, as rapidly worsening thickening can suggest a more aggressive form of the disease.
Blood Tests for Autoantibodies
Once a clinical suspicion of scleroderma is established, blood tests are performed to look for specific autoantibodies, which are proteins produced by the immune system that mistakenly target the body’s own tissues. The initial screening test is the Antinuclear Antibody (ANA) test, which is positive in approximately 95% of patients with systemic scleroderma. Although a positive ANA result does not confirm scleroderma—it is present in many autoimmune conditions—it prompts further, more specialized testing.
If the ANA test suggests a connective tissue disorder, the blood sample is then tested for scleroderma-specific autoantibodies. These specific antibodies are crucial because they not only help confirm the diagnosis but also indicate the subtype of scleroderma and predict the risk of certain organ complications.
Specific Autoantibodies
The presence of Anti-Scl-70, also known as anti-topoisomerase I, is strongly associated with diffuse cutaneous scleroderma and carries a higher risk for interstitial lung disease. Conversely, Anti-Centromere Antibodies (ACA) are most often seen in patients with limited cutaneous systemic sclerosis, a form historically known as CREST syndrome. People with ACA tend to have a lower risk for severe lung scarring but an increased risk for pulmonary arterial hypertension. Another antibody, Anti-RNA Polymerase III, is associated with diffuse disease and carries a high risk for scleroderma renal crisis, a dangerous complication involving high blood pressure and rapid kidney failure.
Evaluating Internal Organ Function
Because scleroderma is a systemic disease, a significant part of the diagnostic process involves assessing for damage to internal organs, which can occur even before symptoms become noticeable. Comprehensive testing is required to measure the function and structure of the lungs, heart, kidneys, and gastrointestinal tract. This information is crucial for planning treatment and determining the long-term outlook.
Lung Assessment
To evaluate the lungs, Pulmonary Function Tests (PFTs) are performed to measure how well the patient breathes and how efficiently oxygen is transferred to the bloodstream, specifically looking at the diffusing capacity of the lung for carbon monoxide (DLCO). A High-Resolution Computed Tomography (HRCT) scan of the chest is also used to identify early signs of interstitial lung disease (ILD), which is scarring of the lung tissue.
Heart and Kidney Assessment
The heart is assessed using an Electrocardiogram (ECG/EKG) to check the electrical activity and rhythm, and an Echocardiogram (Echo) to visualize the heart’s structure and function. The echocardiogram is particularly important for screening for pulmonary hypertension, which is high blood pressure in the arteries of the lungs. For the kidneys, routine blood pressure monitoring is performed, along with urine tests and blood work, to watch for the sudden, severe onset of scleroderma renal crisis.
Gastrointestinal Assessment
If severe gastrointestinal symptoms like difficulty swallowing or persistent heartburn are present, specialized tests such as a barium swallow or esophageal manometry may be ordered to assess the movement of food through the digestive tract.
Confirming the Diagnosis: Biopsies and Specialized Assessments
While physical findings, autoantibody results, and organ function tests are usually sufficient for diagnosis, a skin biopsy may sometimes be performed for confirmation. This procedure involves taking a small sample of affected skin, typically using a punch biopsy tool. The tissue is examined under a microscope for histological findings, often revealing excessive collagen deposits and fibrosis in the deeper skin layers.
A biopsy is helpful when the clinical presentation is unusual or when doctors need to rule out other conditions causing similar skin thickening. The final step is a specialized assessment by the rheumatologist, who integrates all clinical, laboratory, and imaging data to classify the disease and create a personalized treatment plan.