Systemic sclerosis, or scleroderma, is diagnosed according to updated criteria (2013) established by the American College of Rheumatology. These criteria, intended to be more sensitive and allow for earlier diagnosis, set as the primary characteristic of scleroderma measures of skin thickening in the middle part of the fingers (metacarpophalangeal joints). If skin thickening there is absent, seven other observations — with varying levels of importance — are assessed: skin thickening of the fingers, fingertip lesions, telangiectasia, abnormal nailfold capillaries, pulmonary arterial hypertension and/or interstitial lung disease, Raynaud’s phenomenon, and SSc-related antibodies.1

Often in early stages of the disease, Raynaud’s phenomenon may be the only manifestation. A nailfold capillaroscopy, wherein a doctor examines the skin at the base of the fingernail under a microscope, helps determine if Raynaud’s phenomenon is primary (Raynaud’s disease) or is secondary to an autoimmune disorder, such as scleroderma. Blood vessels (capillaries) that appear enlarged or deformed may be a disease indicator.²

In addition to a nailfold capillaroscopy, a complete blood count, complete metabolic panel, muscle enzymes, thyroid function test, and urianalyis will likely be requested. Autoantibodies can help in scleroderma classification, with antinuclear antibodies (ANA) showing positive in 60%–80% of the people with scleroderma. Anticentromere antibodies (ACAs) are positive in 60%–80% of the people with limited scleroderma (CREST), and rarely are positive in people with diffuse systemic scleroderma. Antibodies to topoisomerase-1 (Scl-70 antibodies) are positive in about 30% of the people with diffuse systemic scleroderma

The presence of ACA is highly specific (95%–99%) for a limited scleroderma diagnosis and the presence of anti-Scl-70 antibodies is highly specific for diffuse scleroderma diagnosis. Healthy people rarely have these antibodies, but they may be positive in other rheumatologic conditions.²

What’s next (when scleroderma is diagnosed)?

After a scleroderma diagnosis, the next step is determining its subtype (diffuse or limited), which is based on the extent of skin tightening. The most common skin evaluation score used is the modified Rodnan skin score (MRSS).²

This score is determined through an arbitrarily division of the body into 17 different skin areas. Then, the skin is evaluated by manual palpation, and scores from 0 (uninvolved skin) to 3 (severe thickening) assigned to each area. The total skin score is the sum of the 17 areas, up to a maximum score of 51. The final score correlates with the extent of skin fibrosis, which in turn correlates with the extent of fibrosis and dysfunction likely in internal organs, marked by conditions such as pulmonary fibrosis, scleroderma heart disease, renal disease, and gastrointestinal conditions. The extent of skin thickening should be documented in all follow-up visits.²

Gastric symptoms, such as dysphagia, heartburn, nausea, and vomiting can be investigated through a procedure called endoscopy

Pulmonary function tests, such as spirometry for forced vital capacity (FVC) and diffusion capacity for carbon monoxide, may suggest interstitial lung disease (ILD) if both tests report below normal values. An isolated or disproportionate reduction in diffusion capacity for carbon monoxide relative to FVC may be an indicator of pulmonary hypertension.²

With respect to an accurate pulmonary hypertension diagnosis, a surface echocardiography followed by right-heart catheterization are needed. Follow-up visits should include a 6-minute walk distance assessment to evaluate disease severity and response to therapy.²

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