What is Limited Cutaneous Systemic Sclerosis (LCSS/lcSSc)?
Limited cutaneous systemic sclerosis (lcSSc) is a subset of systemic sclerosis characterized by skin fibrosis restricted to areas distal to the elbows and/or knees (hands, forearms, feet, lower legs), without truncal involvement, though skin thickening may also occur on the face and neck. 1
Disease Classification
lcSSc represents approximately two-thirds of all systemic sclerosis cases and is distinguished from diffuse cutaneous SSc (dcSSc) by both the extent and distribution of skin involvement 2:
- Skin involvement pattern: Fibrosis limited to distal extremities (below elbows/knees), face, and neck 1, 3
- Disease progression: Generally slower, more insidious onset compared to dcSSc 4, 5
- Historical terminology: The CREST syndrome (Calcinosis, Raynaud's phenomenon, Esophageal dysmotility, Sclerodactyly, Telangiectasia) is considered a form of lcSSc 6, 4
Clinical Manifestations
Vascular Features
- Raynaud phenomenon: Present in nearly all patients (>95%) 3, 7
- Digital ulcers: Affect approximately 50% of patients with lcSSc 1, 3
- Pulmonary arterial hypertension: More common in lcSSc than dcSSc, with risk increasing with longer disease duration and older age 3, 4
Organ Involvement
- Gastrointestinal: Affects nearly 90% of patients, with esophageal involvement most common, followed by small bowel hypomotility 1, 3
- Interstitial lung disease: Clinically meaningful in approximately 12% of lcSSc patients (compared to 20% in dcSSc) 1
- Scleroderma renal crisis: Predominantly occurs in early dcSSc, less common in lcSSc 3
Autoantibody Profile
- Anti-centromere antibodies: Frequently associated with lcSSc 3
- Primary biliary cholangitis: Occurs in 8% of lcSSc cases, usually in anti-centromere antibody positive patients 3
Disease Course and Prognosis
lcSSc typically presents with a long history of Raynaud phenomenon before other symptoms develop 4. While generally considered milder than dcSSc, lcSSc can still cause life-threatening complications from small intestine hypomotility and pulmonary arterial hypertension 4, 5.
Clinical Challenges
The appropriate treatment for patients with early lcSSc remains unknown, and further research is needed 1. The lack of interventional studies in lcSSc stems partly from the absence of relevant outcome measures to evaluate this subgroup, as skin involvement is less dynamic than in dcSSc 2.
Key Distinction from Related Entities
- SSc sine scleroderma: A small proportion (1.5-8%) of patients lack definite skin involvement but develop major internal organ complications; these patients often have a similar trajectory to lcSSc 1, 3
- Diffuse cutaneous SSc: Involves skin both distal and proximal to knees/elbows and/or truncal areas, with more rapid progression and earlier widespread internal organ involvement 1, 5