Can we define difficult-to-treat systemic sclerosis?

INTRODUCTION:Systemic sclerosis (SSc) is a chronic autoimmune rheumatic disease characterized by microvascular alterations, immunopathology and widespread fibrosis involving various organs. It is considered difficult to treat due to several reasons: complex pathogenesis, heterogeneity, late diagnosis, limited treatment options for certain organ manifestations, lack of personalized medicine. AREAS COVERED:This review presents the heterogeneity, survival and organ manifestations with their risk factors of systemic sclerosis and their current treatment options, while drawing attention to difficult-to-treat forms of the disease, based on literature indexed in PubMed. EXPERT OPINION:Despite recent advances in the management of SSc over the last decades, the disease presents significant morbidity and mortality. Although available treatment protocols brought significant advancements in terms of survival in SSc-associated interstitial lung disease and pulmonary arterial hypertension, less success has been achieved in the treatment of Raynaud's phenomenon and digital ulcers and the results are modest in case of heart, gastrointestinal, and renal manifestations. There are patients who do not respond to treatment and deteriorate even with adequate therapy. They can be considered difficult-to treat (D2T) cases. We have created a possible score system based on the individual organ manifestations and highlighted treatment options for the D2T SSc category.