More Than Skin Deep: Moving From a Skin-Based Phenotypic Model to Molecular Classification of Systemic Sclerosis

Systemic sclerosis (SSc) is a multisystemic connective tissue disease, characterized by vasculopathy and fibrosis of the skin and visceral organs. It is conventionally classified according to the extent of skin fibrosis into limited cutaneous (lcSSc) and diffuse cutaneous (dcSSc) forms, based on the seminal article of LeRoy et al in 1988.1 According to this classification, lcSSc is characterized by limited skin thickening not extending beyond the elbows and knees, and an association with CREST (calcinosis, Raynaud phenomenon [RP], esophageal dysmotility, sclerodactyly, and telangiectasia) syndrome and pulmonary arterial hypertension (PAH), whereas dcSSc is characterized by proximal and truncal skin thickening, which is rapidly progressive, and greater association with interstitial lung disease (ILD) and scleroderma renal crisis (SRC).1