Current evidence on the effectiveness of systemic herbal medicine for psoriasis: A systematic review with meta- analysis

Herbal medicines have been used to treat psoriasis for many years with anecdotal reports of efficacy which have attracted public attention. We seek to assess the effects of systemic herbal medicine in the treatment of psoriasis. Medical database PubMed/MEDLINE, AMED, CINAHL, and CENTRAL were searched. Randomised controlled trials of systemic herbal medicine used in the treatment of psoriasis included in the meta-analysis. Two reviewers independently applied eligibility criteria, assessed the quality of the trials and extracted data. Any discrepancies were discussed with additional reviewer to achieve consensus. Nine randomised controlled trials met the inclusion criteria. The trials randomised 785 participants. Three RCTs revealed that herbal medicine performed better than placebo control (RR=3.98, 1.3611.62, 95%CI, I2=68%, p=0.01), four RCTs demonstrated that the western drug competitor is superior to herbal medicine(RR=0.73, 0.53-0.97, 95%CI, I2=52%, p=0.03), two RCTs suggested that herbal medicine combined with other medication, (i.e. Auricular Acupuncture or Acitretin (a systemic retinoid), is more effective than herbal medicine alone (RR=1.92, 1.28-2.88, 95%CI, I2=0%, p=0.002). The results of one RCT indicated that herbal medicine reduced the occurrence of adverse reactions of Acitretin, when it was used in combination with herbal medicine. The findings are not conclusive due to the high risk of bias of the included trials and the limited number of trials testing individual herbal medicines. Further well-designed larger scale trials are required to determine the safety and efficacy of oral herbal interventions in the treatment of psoriasis.