Systematic review of topical capsaicin in the treatment of pruritus.
OBJECTIVE
To determine the efficacy of topical capsaicin in treating pruritus in any medical condition.


METHODS
Cochrane library, Medline, Embase, Cinahl and Amed, up to April 2008. No language restrictions.


METHODS
Randomized, controlled trials comparing topically applied capsaicin with placebo or other standard treatment in patients with pruritus, independently selected by two reviewers.


METHODS
Independently extracted by two reviewers. Quality assessed using the Jadad scale.


RESULTS
Six randomized controlled trials were identified for inclusion. Three were for hemodialysis-related pruritus and provided insufficient data for the efficacy of topical capsaicin to be evaluated. A crossover study of capsaicin for treating idiopathic intractable pruritus ani reported a statistically significant difference in responder rates favoring capsaicin over placebo for itching scores but included insufficient data for the validity of this result to be assessed. A study on notalgia paresthetica reported a statistically significant difference in the first phase of a crossover study favoring capsaicin over placebo in a visual analogue scale for itch intensity but failed to report data for a second outcome measure. The final study on brachioradial pruritus used an inappropriate design and reported no significant reduction in itch between capsaicin and placebo.


CONCLUSIONS
At present, there is no convincing evidence for the use of capsaicin to treat pruritus in any medical condition. Further research is needed, and should attempt to address methodological issues identified through this review including unblinding and the suitability of crossover designs.
Complementary Medicine, Peninsula Medical School, University of Exeter and Plymouth, Exeter, UK. sylvia.gooding@pms.ac.uk
Sylvia M D
SM
Gooding
Peter H
PH
Canter
Helen F
HF
Coelho
Kate
K
Boddy
Edzard
E
Ernst
D000982:Antipruritics / Q000627:therapeutic use*; D002211:Capsaicin / Q000627:therapeutic use*; D006801:Humans; D011537:Pruritus / Q000188:drug therapy*; D016032:Randomized Controlled Trials as Topic
D000982:Antipruritics; D002211:Capsaicin