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

Cause

Cholestasis Cholestasis is a condition where the flow of bile from the liver to the duodenum is impaired. The two basic distinctions are: * obstructive type of cholestasis, where there is a mechanical blockage in the duct system that can occur from a gallston ...

means "the slowing or stopping of

bile Bile (from Latin ''bilis''), also known as gall, is a yellow-green/misty green fluid produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is primarily composed of water, is pro ...

flow" which can be caused by any number of diseases of the

liver The liver is a major metabolic organ (anatomy), organ exclusively found in vertebrates, which performs many essential biological Function (biology), functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of var ...

(which produces the bile), the

gallbladder In vertebrates, the gallbladder, also known as the cholecyst, is a small hollow Organ (anatomy), organ where bile is stored and concentrated before it is released into the small intestine. In humans, the pear-shaped gallbladder lies beneath t ...

(which stores the bile), or

biliary tract The biliary tract (also biliary tree or biliary system) refers to the liver, gallbladder and bile ducts, and how they work together to make, store and secrete bile. Bile consists of water, electrolytes, bile acids, cholesterol, phospholipids an ...

(also known as the biliary tree, the conduit that allows the bile to leave the liver and gallbladder and enter the small intestine). When this occurs,

conjugated bilirubin Bilirubin (BR) (adopted from German, originally bili—bile—plus ruber—red—from Latin) is a red-orange compound that occurs in the normcomponent of the straw-yellow color in urine. Another breakdown product, stercobilin, causes the brown ...

and the waste products that usually would be cleared in bile reflux back into the bloodstream. This causes a primarily conjugated hyperbilirubinemia and

jaundice Jaundice, also known as icterus, is a yellowish or, less frequently, greenish pigmentation of the skin and sclera due to high bilirubin levels. Jaundice in adults is typically a sign indicating the presence of underlying diseases involving ...

; 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 Bilirubin (BR) (adopted from German, originally bili—bile—plus ruber—red—from Latin) is a red-orange compound that occurs in the normcomponent of the straw-yellow color in urine. Another breakdown product, stercobilin, causes the brown ...

which is the water-insoluble form that is bound to serum

albumin Albumin is a family of globular proteins, the most common of which are the serum albumins. All of the proteins of the albumin family are water- soluble, moderately soluble in concentrated salt solutions, and experience heat denaturation. Alb ...

; the liver has not had a chance to conjugate the bilirubin yet and can be caused either because too much

unconjugated bilirubin Bilirubin (BR) (adopted from German, originally bili—bile—plus ruber—red—from Latin) is a red-orange compound that occurs in the normcomponent of the straw-yellow color in urine. Another breakdown product, stercobilin, causes the brown ...

is made (such as in massive

hemolysis Hemolysis or haemolysis (), also known by #Nomenclature, several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may ...

ineffective erythropoiesis Ineffective erythropoiesis a condition in which the bone marrow produces red blood cells (erythrocytes) that are unable to mature properly and are pre-maturely destroyed due to various causes. Erythropoiesis is the overall process that the body goe ...

) or because too little is conjugated ( Gilbert's disease or

Crigler–Najjar syndrome Crigler–Najjar syndrome is a rare inherited autosomal recessive disorder affecting the metabolism of bilirubin, a chemical formed from the breakdown of the heme in red blood cells. The disorder results in a form of non hemolytic jaundice, whic ...

). Unconjugated hyperbilirubinemia does not typically cause pruritus. It is thought that bile salts that deposit into the skin are responsible for the pruritus (itching) 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 (and therefore cannot make these products to begin with) 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.

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{{Dermatitis and eczema Pruritic skin conditions

Cause

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