Scleroderma is a chronic autoimmune disease in which the immune system mistakenly attacks healthy tissues in the body. This induces an overproduction of collagen, a component of scar tissue, leading to the formation of patches of thick and hardened skin that characterize the disease. Excess collagen may also accumulate in different organs, causing damage.
Different types of scleroderma have different symptoms. The disease can be grouped broadly as localized scleroderma, which usually affects the skin only, or systemic scleroderma, when internal organs are also affected.
No single test is able to diagnose scleroderma, and several tests may be needed to exclude other conditions before a definitive diagnosis is reached. Tests also may be carried out as part of the diagnosis to see which organs the disease has affected.
A physical examination will be done by a doctor to check for the common symptoms of scleroderma, such as skin changes. This includes the typical thick or tight patches of skin, sores on the fingers or toes, or calcium deposits under the skin (called calcinosis).
The doctor also may ask about other common symptoms, such as heartburn, difficulty swallowing, fatigue, breathlessness, joint pain, or Raynaud’s phenomenon, when fingers and toes feel numb or prickly in response to cold temperatures or stress.
A biopsy involves removing a small tissue sample to be examined under a microscope and tested in a laboratory. A skin biopsy may be taken from an altered patch of skin to help diagnose scleroderma. Clinicians will test the biopsy for characteristic signs of the disease, such as calcinosis or changes in blood vessels of the skin.
A skin biopsy alone, however, cannot differentiate between localized or systemic scleroderma, so further tests will be needed to determine whether internal organs are affected.
Blood tests are commonly used to diagnose scleroderma, as they can identify the presence of autoantibodies. Antibodies are proteins normally produced by the immune system to help fight disease-causing invaders. Autoantibodies are antibodies that, rather than targeting a foreign invader like a virus, target the body’s own healthy tissue.
The vast majority of scleroderma patients have detectable blood levels of antinuclear antibodies (ANA; against the cell nucleus). The presence of ANA alone does not confirm a diagnosis of scleroderma, as it can be present in other immune disorders such as lupus.
Blood tests can also reveal whether kidney function has been affected, which can occur in systemic disease.
Tests for Raynaud’s phenomenon
Raynaud’s phenomenon is one of the most common symptoms of scleroderma. Tests for Raynaud’s may include:
- Thermography on the hands, which uses an infrared camera to detect the level of heat generated in response to cold water.
- Nailfold capillaroscopy, which examines the small blood vessels under the fingernails.
Lung function tests
The lungs, or the blood vessels of the lungs, are commonly affected in people with systemic scleroderma. The lungs need to be stretchy and flexible in order to inflate and deflate when breathing; in systemic scleroderma, excess scar tissue can make them stiff, and breathing more difficult. Tests may be done to assess how well the patient can breathe.
Imaging tests, such as a chest X-ray or a CT scan, may be needed, as this can reveal abnormalities such as a buildup of scar tissue in the lungs.
Heart function tests
Systemic scleroderma often affects the heart, either through scarring of the heart tissue itself, or via conditions such as pulmonary arterial hypertension (PAH) putting strain on the heart. Two tests commonly used to assess the heart rhythm and function are:
- Electrocardiogram, which measures electrical signals across the heart, and can detect changes in heart muscle caused by the disease.
- Echocardiogram, which uses ultrasound to produce an image of the heart and can assess structural abnormalities.
The digestive system can be affected by systemic scleroderma, which can be detected through an endoscopy. This involves inserting a small flexible tube with a camera through the mouth or nose, to check for abnormalities in the esophagus (connects mouth with stomach) and intestines.
Manometry, a test that measures the strength of muscles in the esophagus, may also be used to assess swallowing difficulties.
Last Updated: May 6, 2021
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