Systemic Sclerosis Overlap Syndromes

There is clinical overlap between systemic sclerosis and other autoimmune rheumatic diseases. This likely arises through shared genetic and environmental factors in etiopathogenesis. Up to one-fifth of patients fulfilling the 2013 ACR/EULAR classification criteria for systemic sclerosis demonstrate some clinical or laboratory features of other relevant diseases, such as myositis, arthritis, SLE, Sjogren’s, or vasculitis. Recent studies suggest that these cases may have a specific profile based on peripheral whole-blood RNA analysis. Identification of overlap cases is important clinically as the other disease manifestations may require specific treatment, and clinical outcomes can reflect the broad range of clinical features beyond systemic sclerosis.