Acute severe ulcerative colitis management: unanswered questions and latest insights

: Acute severe ulcerative colitis (ASUC) is a distinctive ulcerative colitis flare presentation characterised by the presence of systemic inflammation as well as bloody diarrhoea, and occurs at least once in 25% of patients with ulcerative colitis during their disease course. Each episode carries a risk of complications, need for colectomy, and mortality. Little is known about ASUC pathogenesis, although impaired host-microbiota crosstalk involving pathobionts is suspected. In this Review, we discuss unanswered questions and results from the latest research on the medical-first-line, second-line, and potential third-line therapies-and surgical management of ASUC. We detail promising options for management, such as the use of enteral nutrition in combination with intravenous steroids, the ability to predict early failure of first-line or second-line therapies, and the emerging role of JAK inhibitors. An optimal framework to personalise therapy on the basis of multiomics tools is yet to be developed.