When the liver cannot release bile into the small intestine, it builds up and spills over into the blood stream. This bilirubin irritates the sensory nerves and you brain interprets this as an itch.
Itching is one of the symptom of this disease. Bile products deposited in the skin may cause severe itching. >>> read more about it here >> digestive.niddk.nih.gov
Can persistant itching in the same site be a manifestation of viral hepatitis?
What is the treatment of iching due to cancer liver