Diffuse cutaneous systemic sclerosis (dcSSc) is a subtype of Systemic Sclerosis (SSc; see this term) characterized by truncal and acral skin fibrosis with an early and significant incidence of diffuse involvement (interstitial lung disease, oliguric renal failure, diffuse gastrointestinal disease, and myocardial involvement).
The prevalence is estimated at about 1/25,000 adults. Women are predominantly affected (F/M sex ratio around 4:1).
The disease usually manifests at between 40 and 50 years of age. Pediatric onset can occur but is extremely rare. Raynaud's phenomenon is often the first sign of the disease. The other signs usually appear a few months later. Skin hardening first occurs on the fingers and face, but rapidly becomes generalized. Telangiectasias are sometimes present on the thorax, face, lips, tongue, and fingers. Tendon friction rubs are observed. Esophageal dysmotility is common and provokes gastroesophageal reflux and sometimes dysphagia. Gastrointestinal malabsorption and dysmotility may also be present and are associated with weight loss, vomiting, diarrhea or occlusion. Dry mouth and dental involvement can occur. Arthralgias and acroosteolysis are frequent. Muscular involvement can lead to muscular pain and weakness, and cramps. Severe life-threatening renal involvement may occur (about 2% of cases). Pulmonary fibrosis is frequently seen (60% of cases). Pulmonary hypertension may also occur (10-15% of cases).
The exact cause of diffuse cutaneous SSc is unknown. The disease originates from an autoimmune reaction which leads to overproduction of collagen. In some cases, the condition is associated with exposure to chemicals (including silica, solvents and hydrocarbons).
Diagnosis is based on typical clinical manifestations and on evidence of specific microangiopathy with giant loops on nailfold capillaroscopy. Skin biopsy is usually not needed. Blood tests must be performed, and show typical antitopoisomerase autoantibodies in 30-40% of cases. The extent of the disease should be evaluated by computed tomography (CT), electrocardiogram, echocardiography, radiography of the hands and esophageal and gastric fibroscopy if needed.
Differential diagnoses include Sharp syndrome, systemic lupus erythematosus, antiphospholipid syndrome, polyarteritis nodosa, polymyositis, and rheumatoid arthritis (see these terms).
Management is mostly symptomatic. Raynaud's phenomenon can be treated with calcium channel blockers. Proton pomp inhibitors are given for gastric reflux. Surgical resection of severe calcinosis may be required. Low doses of corticosteroids with immunosuppressive agents are needed in cases with recent severe cutaneous involvement or in progressive lung fibrosis. Pulmonary vasodilators are given in case of pulmonary arterial hypertension. Patients require regular clinical follow-up with early pulmonary function tests and echocardiography.
The prognosis is severe (10-year survival rate of 60-80%) because of the high risk of life-threatening complications: renal crisis, severe digestive involvement, severe lung fibrosis, and, sometimes, severe heart involvement and pulmonary arterial hypertension.
Last update: July 2010