The role of mast cell activation in cholestatic pruritus.

Jaundiced patients experience intense pruritus, the pathophysiology of which is unclear. In this study, blood histamine concentrations, skin mast cell counts and intracellular histamine concentrations in peritoneal mast cells were examined in an experimental model of biliary obstruction. Three weeks after bile duct ligation (BDL), total blood histamine concentrations were significantly elevated compared with those from control animals (p < 0.0001). Skin mast cell counts were increased (p < 0.05) and peritoneal mast cell histamine content decreased (p < 0.05) in jaundiced animals. These results demonstrate that mast cells degranulate in biliary obstruction with consequent release of histamine into the systemic circulation. This may contribute to cholestatic pruritus. These data may have significant pharmacological implications in patients with obstructive jaundice.