Cholestatic pruritus: effect of phototherapy on pruritus and excretion of bile acids in urine.

Pruritus associated with hepatic cholestasis may cause significant morbidity and its correlation to retention of bile acids in skin is inconsistent. Available treatment modalities are only partially effective and can have several adverse effects. Phototherapy has recently been reported to improve cholestatic pruritus, but has not been evaluated previously in children, and its mechanism is still unclear. We report the outcome of multiple Daylite phototherapy treatments over two years in a seven-year-old child with chronic hepatic cholestasis that was resistant to other therapeutic modalities. Bile acid levels in urine were used as markers of effectiveness in parallel with clinical response. Night phototherapy alone increased the bile acids/creatinine ratio in urine from 1.54 +/- 0.04 mumol/mg at baseline to 2.07 +/- 0.29 mumol/mg. Continuous phototherapy combined with night diuresis raised the ratio further to 2.28 +/- 0.55 mumol/mg. Night diuresis alone had no effect. Continuous phototherapy combined with night diuresis raised the bile acids/creatinine ratio by 44% on the first day and by 61% on the second day, but declined to baseline on the third day of treatment. A marked clinical improvement was noted for one week following two days of phototherapy. This schedule has been repeatedly effective in improving pruritus for approximately one year and may be due to the ability of phototherapy to enhance excretion of bile acids and other possible pruritogens into urine.