Topical capsaicin therapy in humans with hemodialysis-related pruritus.

As shown in previous experimental studies, topical capsaicin has a strong inhibitory effect in histamine-induced itch in healthy persons, but not in patients with atopic eczema. However, in serotonin-induced itch, it was not a sufficient antipruritic. Eleven pruritic patients on hemodialysis (HD) and ten controls were treated with capsaicin 0.05% liniment on the upper back three times daily for 5 days. Study parameters to be investigated were wheal and flare reactions, itch and alloknesis (perifocal itch sensation induced by usually non-itching stimuli) after serotonin and histamine iontophoresis in treated and untreated skin. There were no significant differences in any parameter before and after HD. In both groups, itching was not significantly reduced by capsaicin compared to untreated skin. Itching, however, was significantly lower in capsaicin-pretreated patients when comparing to controls. In summary, topical capsaicin showed some antipruritic potency in HD patients in this experimental model and may therefore be considered as a co-medication in HD patients.