The Updated Role of Ultrasound in Assessing Dermatological Manifestations in Systemic Sclerosis

Systemic sclerosis (SSc), an autoimmune connective tissue disease, characterized by skin fibrosis, increased dermal thickness and microvascular involvement. Fibroblasts and myofibroblasts deposit excessive amounts of collagenous and non-collagenous extracellular matrix components in the skin. This leads to microvascular abnormalities and Raynaud's phenomenon, with painful digital ulcers (DU) at the fingertips adding to patient discomfort. The skin involvement and severity in SSc was evaluated by the Modified Rodnan skin score (mRSS). Although high-frequency ultrasound (HUS) has been widely researched in the study of skin thickness and DU in SSc, its adoption into clinical practice is not yet common. However, novel insights into the still relatively unknown disease pathogenesis in SSc and its evaluation may be provided by HUS, including early (pre-clinical) skin involvement. It may also be useful in both the evaluation and follow-up of DU. Indeed, it is a non-invasive, safe, inexpensive and reproducible method able to assess not only SSc patients' cutaneous structural changes, but also their vascular system changes. Moreover, several recent studies have reported that elastosonography (ES) is of use when investigating skin involvement in systemic sclerosis. This review aims at providing information as to role HUS and ES play in research advancements and the clinical perspectives in the evaluation of skin thickness and DU in SSc patients.