DEFINITION AND CLASSIFICATION
Systemic sclerosis (SSc) is a complex and clinically heterogeneous orphan disease with protean clinical manifestations, a chronic and frequently progressive course, and significant disability, disfigurement and mortality. Virtually every organ can be affected (Fig. 353-1).
Multi-organ involvement in systemic sclerosis. Prominent complications more common in diffuse cutaneous SSc are shown in red; more common in limited cutaneous SSc in blue; and common in both forms of SSc shown in black.
There is marked variability among SSc patients in patterns of skin involvement, organ complications, rates of disease progression, response to treatment, and survival. The early stages of SSc are associated with prominent inflammatory features; however, over time, structural alterations in multiple vascular beds and progressive visceral organ dysfunction due to fibrosis and atrophy come to dominate the clinical picture. Classification criteria for diagnosis of SSc are shown in Table 353-1.
TABLE 353-1Classification Criteria for Diagnosis of Systemic Sclerosis ||Download (.pdf) TABLE 353-1 Classification Criteria for Diagnosis of Systemic Sclerosis
|ITEM ||SUB-ITEM ||WEIGHT/SCORE |
|Skin thickening (bilateral)—fingers extending proximal to MCP joints || ||9 |
|Skin thickening of fingers only || |
Sclerodactyly (skin thickened distal to MCP joints)
|Fingertip lesions ||Digital tip ulcer or pitting scar || |
|Mucocutaneous telangiectasia || ||2 |
|Abnormal nails capillary pattern || ||2 |
|Lung involvement || |
Interstitial lung disease
|Raynaud’s phenomenon || ||3 |
|SSc-specific autoantibodies || |
RNA polymerase III
Although thick and indurated skin (scleroderma) is the distinguishing hallmark of SSc, skin changes also occur in localized forms of scleroderma, along with multiple metabolic, inherited and autoimmune disorders (Table 353-2). Patients with SSc can be broadly segregated into two major subsets defined by the pattern of skin involvement, clinical and laboratory features, and natural history (Table 353-3). Diffuse cutaneous SSc (dcSSc) is typically associated with extensive skin induration starting in the fingers (sclerodactyly) and ascending from distal to proximal limbs and the trunk. In these patients, interstitial lung disease (ILD) and acute renal involvement develop relatively early. In contrast, in patients with limited cutaneous SSc (lcSSc), Raynaud’s phenomenon generally precedes other disease manifestations, sometimes by years. In these patients, skin involvement remains confined to the fingers, distal limbs, and face, while the trunk is spared. The constellation of calcinosis cutis, Raynaud’s phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia, was historically termed the CREST syndrome. In lcSSc, visceral organ involvement tends to show insidious progression, and digital ischemic ulcers, pulmonary arterial hypertension (PAH), hypothyroidism, and primary biliary cirrhosis may occur as late complications. In some patients, Raynaud’s phenomenon and characteristic clinical and laboratory features of SSc occur in the absence of detectable skin thickening. This syndrome has been termed SSc ...