Cholestatic pruritus


Cholestatic pruritus is the sensation of itch due to nearly any liver disease, but the most commonly associated entities are primary biliary cirrhosis, primary sclerosing cholangitis, obstructive choledocholithiasis, carcinoma of the bile duct, cholestasis, and chronic hepatitis C viral infection and other forms of viral hepatitis.

Overview of cholestatic pruritus

means "the slowing or stopping of bile flow" which can be caused by any number of diseases of the liver, the gallbladder, or biliary tract. When this occurs, conjugated bilirubin and the waste products that usually would be cleared in bile reflux back into the bloodstream. This causes a primarily conjugated hyperbilirubinemia and jaundice; the liver conjugates the bile to make it water-soluble and because the bile has already been processed by the liver, when it gets backed up because of a blockage and is refluxed into the blood, the blood will have high levels of conjugated bilirubin. This is in contrast to primarily unconjugated hyperbilirubinemia which is the water-insoluble form that is bound to serum albumin; the liver has not had a chance to conjugate the bilirubin yet and can be caused either because too much unconjugated bilirubin is made or because too little is conjugated. Unconjugated hyperbilirubinemia does not typically cause pruritus.
It is thought that bile salts that deposit into the skin are responsible for the pruritus because the levels of bilirubin in the bloodstream and the severity of the pruritus does not appear to be highly correlated. Patients that have been administered bile salt chelating agents do report some relief, however, and patients that have complete liver cell failure do not have pruritus. This suggests that products made by the liver must have some role in pruritus although it is not known exactly which product is responsible.