Efficacy of Externally Applied Chinese Herbal Drugs in Treating Psoriasis: A Systematic Review

Objective: To assess the efficacy and safety of external application of Chinese herbal drugs (exCHD) in the treatment of psoriasis. Methods: Literature regarding randomized clinical trials (RCTs) of psoriasis treatments with ex-CHD, either alone or combined with Western medicine (WM) or physiotherapy, controlled by untreated, placebo or WM treatment were found in electronic databases, including PubMed/MEDLINE, EMBASE, Cochrane Library, Cochrane Central Register of Controlled Trials, China Biology Medicine Disc (CBM), Chinese National Knowledge Infrastructure (CNKI), Wanfang database and VIP database from their inception through July 2011. Study selection, data extraction, quality assessment, and data analyses were conducted according to the Cochrane standards. Results: A total of 10 randomized trials (involving 1,435 patients) were included. Because both test and control drugs used in the RCTs were different from each other, the effects can only be described singly and calculated. Regarding the total effective rate for the treatment of psoriasis, exCHD in combination with ultraviolet radiation b (UVB) or narrow band ultraviolet radiation b (NB-UVB), which was reported in 6 trials, was superior to UVB alone. One study reported that ex-CHD and externally applied WM had equivalent effects. In another study, ex-CHD showed better results than placebo. However, another two comparisons of ex-CHD and WM (all in combining with oral WM) showed uncertain outcomes. Nine trials reported adverse reactions. Of these, 7 RCTs included statistical analysis. The results showed that the side-effects that occurred in ex-CHD combined with UVB were less severe than those caused by UVB alone, but the incidence was roughly the same as WM. Conclusion: The evidence supporting the efficacy of ex-CHD with respect to treating psoriasis is quite limited and must be strengthened by high-quality studies.