Update: primary biliary cholangitis, primary sclerosing cholangitis, and IgG4-associated cholangitis New studies, definitions, and therapies for rare biliary diseases

Background: Untreated cholestatic liver diseases can lead to liver cirrhosis with life-threatening complications or the need for transplantation. Primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and IgG4-associated cholangitis (IAC) are possible triggers of chronic cholestasis as primary biliary diseases. Despite their unclear etiology, there have been recent improvements and new insights regarding their treatment and surveillance.Objective: To summarize the basic principles and relevant clinical/translational studies on PBC, PSC, and IAC.Materials and methods: Research/summary of German and European guidelines, as well as relevant research findings, including those from international research associations.Results: The clinical course of primary biliary diseases varies significantly depending on the entity. Stricter criteria for successful therapy are emerging for PBC, with bezafibrate (off-label) and obeticholic acid (OCA) being effective second-line medications. For PSC, there is still a lack of approved drugs to significantly impact disease progression, although new agents have shown a reduction in cholestasis in phase II trials. Bezafibrate, among others, exhibits good efficacy in treating pruritus. IAC, as a rare differential diagnosis, usually manifests in later life and often affects multiple organ systems. It typically responds well to immunosuppressive therapy.Conclusion: Timely diagnosis remains crucial for successful management of primary biliary diseases, enabling the initiation of therapy or surveillance measures. In particular, with regard to disease-associated symptoms such as pruritus, affected patients now have access to a broader variety of medications.