A 25-year-old medical student with primary sclerosing cholangitis (PSC) and ulcerative colitis in remission comes to the outpatient clinic with worsening itch complaints particularly on the arms and lower legs. Scratch lesions on the lower legs are seen. He describes itch intensity in the late evening as 6-7 on a number rating scale of 0-10. His actual medical treatment includes ursodeoxycholic acid (15 mg/kg daily) and mesalazine (2 g daily). His serum liver tests disclose a serum alkaline phosphatase of 2.5 x the upper limit of normal (ULN) and gamma-GT of 3 x ULN, but normal bilirubin. A high quality MRCP excludes relevant intra- and extrahepatic bile duct strictures but confirms mainly intrahepatic bile duct irregularities with stenoses and mild dilatations typical for PSC.