Pilot study of bright-light therapy reflected toward the eyes for the pruritus of chronic liver disease

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. 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). 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. 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.