A DOUBLE-BLIND EVALUATION OF TOPICAL CAPSAICIN IN PRURITIC PSORIASIS

Background. Substance P, an undecapeptide neurotransmitter, has been i mplicated in the pathophysiology of psoriasis and pruritus. Objective. Safety and efficacy of topical capsaicin, a potent substance P deplet or, were evaluated in patients with pruritic psoriasis. Methods. Patie nts applied capsaicin 0.025% cream (n = 98) or vehicle (n = 99) four t imes a day for 6 weeks in this double-blind study. Efficacy was based on a physician's global evaluation and a combined psoriasis severity s core including scaling, thickness, erythema, and pruritus. Results: Ca psaicin-treated patients demonstrated significantly greater improvemen t in global evaluation (p = 0.024 after 4 weeks and p = 0.030 after 6 weeks) and in pruritus relief (p = 0.002 and p = 0.060, respectively), as well as a significantly greater reduction in combined psoriasis se verity scores (p = 0.030 and p = 0.036, respectively). The most freque ntly reported side effect in both treatment groups was a transient bur ning sensation at application sites. Conclusion: Topically applied cap saicin effectively treats pruritic psoriasis, a finding that supports a role for substance P in this disorder.