Objective: It is proposed that the pruritus of cholestasis is, in part, centrally mediated by endogenous opioid peptides. The expression of these peptides and their receptors on neurons displays a circadian rhythm, as does the scratching activity in patients with cholestasis and pruritus. Because light has regulatory effects on circadian rhythms via retinothalamic pathways, we hypothesized that bright-light therapy (BLT) reflected toward the eyes might alter the pruritus of cholestasis. To test this hypothesis, we studied the effect of BLT on this form of pruritus.
Methods: Eight patients with chronic liver disease of different etiologies and pruritus were studied in an open-label, pilot study of 8-wk duration. BLT (10,000 lux) was administered for up to 60 min twice a day. Pruritus was assessed subjectively by a visual analog scale from which a visual analog score (VAS) was derived, and objectively, by a scratching activity monitoring system that recorded hourly scratching activity (HSA).
Results: In seven of the eight patients studied, the mean HSA was lower during BLT. BLT was associated with a mean decrease in HSA of 32.2% (p = 0.123). The mean VAS for pruritus was lower in six patients during BLT; the mean VAS score derived from the eight patients studied decreased by 42% (p = 0.05) during treatment.
Conclusions: The results of this short-term study suggest that the pruritus of cholestasis is responsive to bright light reflected toward the eyes and that in some patients, BLT may ameliorate this form of pruritus.