Shuiniujiao Dihuang Decoction With Variation for the Treatment of Psoriasis

Psoriasis is an inflammatory skin disease with huge negative impact on the quality of life of the patients, and has an overall prevalence of 2% to 3% in the general population. Plaques psoriasis is the most common type of the disease and presents red, well demarcated, and silvery plaques mainly localized in the umbilical and lumbosacral area as well as in the elbows, knees, and scalp.

Currently, pharmacological treatments such as retinoids, corticosteroids, vitamin D analogs and biologics remain the main options for most psoriasis patients. However, side effect and high cost barred many ordinary psoriasis patients from benefiting from the treatments.

A Chinese medicine formula "Shuiniujiao Dihuang Decoction with Variation (SDD)" was prescribed by Prof. Lin for many years and observed to be effective in relieving psoriasis patients' clinical manifestations.

In this study, subjects with psoriasis will be randomized into treatment group of "SDD" or placebo group for 12 weeks.

Psoriasis is an inflammatory skin disease with huge negative impact on the quality of life of the patients, and has an overall prevalence of 2% to 3% in the general population. Plaques psoriasis is the most common type of the disease and presents red, well demarcated, and silvery plaques mainly localized in the umbilical and lumbosacral area as well as in the elbows, knees, and scalp. The major histological features of psoriasis include epidermal hyperplasia with aberrant keratinocyte differentiation, pronounced inflammatory cell infiltration and increased vascularization. Currently, pharmacological treatments such as retinoids, corticosteroids, and vitamin D analogs remain the main options for most psoriasis patients. However, the efficacy of conventional drugs is limited because of adverse side effects and the development of pharmacoresistance. Recently, biologics have become available for the treatment of acute and subacute plaque psoriasis with excellent response rate. However, the high costs involved with the biologics have barred many ordinary psoriasis patients from benefiting from this new class of anti-psoriatic medication.

Natural products are valuable sources in novel drug development. Shuiniujiao Dihuang Decoction with Variation (SDD) is an empirical formula of the Principal Investigator (Prof. Zhi-Xiu Lin), a highly experienced Registered Chinese Medicine Practitioner and Chinese medicine dermatologist working at the School of Chinese Medicine, The Chinese University of Hong Kong. SDD has been prescribed in clinic in Hong Kong for many years and observed to be effective in relieving psoriasis patients' clinical manifestations. SDD contains 23 Chinese herbal medicines, including Rehmanniae Radix (Dihuang), Bubali Cornu (Shuiniujiao), Paeoniae Radix Rubra (Chishao), Moutan Cortex (Mudanpi), Scrophulariae Radix (Xuanshen), Ophiopogonis Radix (Maidong), etc. The formula is composed of herbal medicines that can eliminate pathogenic heat, expel blood stasis and dampness, nourish yin, and have antipruritic effect.

A randomized, double-blinded, placebo-controlled trial will be conducted to evaluate the efficacy of SSD on psoriasis patients. Clinical evidence for the anti-psoriatic effects of SSD is a necessary step towards developing this Chinese medicine formula into an anti-psoriatic pharmaceutical agent.

Eligibility Criteria:
Inclusion Criteria:

* Mild to moderate chronic plaque psoriasis (PASI score 3 to 12).
* Willingness to give informed consent.

Exclusion Criteria:

* Pustular or generalized erythrodermic psoriasis.
* Psoriatic arthritis with syndrome of spleen-kidney yang deficiency according to Chinese medicine theory.
* Systemic therapy for psoriasis 6 months prior to baseline.
* Use topical medications for psoriasis 14 days prior to baseline such as retinoids, corticosteroids, vitamin D analogues, tazarotene and tacrolimus.
* Has taken any antibiotics, probiotics and prebiotics 30 days prior to baseline.
* UV light therapy 30 days prior to baseline.
* Clinically significant laboratory abnormality in blood, liver or renal functions (≥1.5 times the upper limit of reference range).
* History of allergy to Chinese herbs.
* Known pregnant or lactation, or have a plan to conceive in 6 months.
* Known active gastric or duodenal ulcer, or severe arrhythmia.
* Unwillingness to comply with study protocol.
* Any other condition that in the opinion of the investigators could disadvantage the subject.