Raised histamine concentrations in chronic cholestatic liver disease

Pruritus is a frequent symptom in chronic cholestatic liver disease. To date, no single causative mechanism has been identified. We examined venous plasma concentrations of the known pruritogen, histamine, using a highly sensitive radioenzymatic assay in 42 patients with chronic cholestatic liver disease, and in normal controls. The mean plasma histamine level was significantly greater in chronic cholestatic liver disease patients (275 (117) pg/ml; x (SD) than in controls (140 (72) pg/ml, n=20) (p<0·0001). No significant differences were found between histamine concentrations in the two chronic cholestatic liver disease subgroups: primary biliary cirrhosis and sclerosing cholangitis. Histamine concentrations were significantly greater (p<0·01) in the pruritic (319 (132) pg/ml) as compared with the non-pruritic (227 (75) pg/ml) chronic cholestatic liver disease patients. The histaminase activity was equivalent in patients and controls. The finding of raised histamine concentrations in chronic cholestatic liver disease suggests in vivo mast cell activation and a potential role for its mediators in the pruritus characteristic of these disorders.