Systemic sclerosis (SSc) is a chronic autoimmune connective tissue disease characterized by excessive collagen deposition in the skin and internal organs, such as the gastrointestinal tract, kidney, heart, and lungs. Symptoms result from vascular dysfunction, inflammation, and progressive fibrosis, which lead to occlusion of the microvasculature.
As a result of the vascular injury, complications such as PAH and digital ulcers (DU) can occur.
Around 40% – 50% of SSc patients suffer from Digital ulcers at least once in their disease history. DUs are very painful and result in difficult-to-heal open sores on fingers and toes. They leave depressed scars and adversely affect the patient’s ability to perform work and daily activities, particularly those associated with fingertip functions. In severe cases, infection can become a complication, leading to osteomyelitis and gangrene, for which surgery and even amputation may be required.
Endothelin (ET) plays a key role in the underlying vasculopathy of DUs. The pathway leading to the vasculopathy of DUs is similar to that of PAH, involving excessive vasoconstriction and subsequent vascular remodeling. DUs are visible evidence of vasculopathy in SSc.