Psoriasis is a common chronic relapsing inflammatory skin disease with a prevalence of 2% to 4% [1]. Although the underlying cause of psoriasis is not fully understood, it is generally believed that the disease is associated with genetic, metabolic, immunological, endocrinal, and infective etiologies [2]. Psoriasis, particularly the refractory plaque psoriasis, can have considerable detrimental effects on patient quality of life. In Western medicine (WM), treatments for psoriasis, including the use of topical corticosteroids, vitamin D derivatives, calcineurin inhibitors, systemic phototherapy, acitretin, cyclosporine A, immunosuppressants, and biological agents [3], can alleviate the clinical symptoms to varying degrees; however, potential safety problems and high costs can often limit clinical application.
The treatment of psoriasis using traditional Chinese medicine (TCM) has a long history, with earliest records being traced back to more than 1400 years ago. This treatment is based on a complete theoretical system, which has evolved progressively in response to developments in science and technology and the considerable changes in lifestyle. A series of systematic reviews of TCM in clinical practice have indicated that this approach is effective in the treatment of psoriasis [4–10], and clinical and experimental data indicate that TCM can modify psoriasis by antagonizing or regulating interleukin and the IL–23/IL–17 axis to inhibit the main causal pathways [11].
In a clinical trial conducted by our research team, we found that treatment with Jueyin prescription (JYP), a compound Chinese herbal preparation containing seven constituents (i.e., abalone shell, honeysuckle, tree peony bark, dried Rehmannia root, Hedyotis diffusa, folium, and turmeric root-tuber; see Table 1 for details), is safe and effective in patients with early-stage psoriasis [12]. The mechanism of action of this preparation is believed to be related to the inhibition of keratinocyte proliferation, enhancement of epidermal parakeratosis, and a reduction in the expression of nitric oxide and malondialdehyde[13]. These assumptions have accordingly been verified in in vitro studies, in which a 5% JYP was observed to have a significant inhibitory effect on the proliferation of HaCaT cells, with primary effects on the G1 phase of the cell cycle [14]
In TCM, moving cupping therapy is a type of acupuncture therapy that is often used in China and other Asian countries, and is gradually being accepted worldwide, owing to its simplicity, convenience, and effectiveness [15].Compared with oral Chinese medicine alone, a more pronounced decrease in psoriasis area and severity index (PASI) score has been recorded in psoriasis patients treated with moving cupping therapy combined with TCM [16]. In this type of therapy, a vacuum is generated by heating the air in a tank with a flame, and cupping produces a mild attraction in the skin, which is characterized by a strong adsorptive force and a deep action on skin lesions. Coupled with the rapid push and pull of the can body at the site of skin damage, moving cupping can activate qi and blood circulation, dissipate blood stasis, regulate meridians and collaterals, and stimulate the vitality of the body to strengthen resistance and eliminate pathogenic factors. Previous studies have shown that moving cupping therapy combined with TCM ointment is effective in the treatment of plaque psoriasis, with an effect equivalent to that obtained following exposure to narrow-band ultraviolet B radiation (NB-UVB) combined with externally applied capotriol ointment [17].
NB-UVB phototherapy is a common and effective method for the treatment of plaque psoriasis, for which an optimal wavelength of 313 nm has been demonstrated to have high efficacy and a low side-effect profile [18, 19]. UV light has been shown to have effects on various components of the natural and acquired immune responses and is related to a depletion of Langerhans cells and T cells in the epidermis [20–22]. Previous studies have indicated that in patients with psoriasis, the serum levels of 25-hydroxyvitamin D increase in response to NB-UVB treatment, and that there is a correlation between this increase and the number of therapy sessions [23]. Moreover, changes in the skin microflora following UVB treatment may be related to treatment response [24].These findings thus indicate that the effectiveness and safety of phototherapy on psoriasis may depend on a complex interaction of immunological and metabolic mechanisms. In addition, according to clinical reports, compared with exposure to NB-UVB alone, NB-UVB combined with a TCM-medicated bath can improve the curative effect, reduce the cumulative dose, and lessen the adverse reactions of UV radiation [25].
Whereas TCM and WM are both commonly used in the treatment of psoriasis, and each has associated advantages and characteristics, the combined application of these two approaches can enhance the curative effect and reduce side effects and the rate of recurrence. Accordingly, it is not surprising that the combination of TCM and WM therapies, adjusted according to the situation, is widely used in clinical practice. However, to the best of our knowledge, there have been no previous clinical studies that have examined the hierarchical selection of treatment combinations according to the severity of skin lesions. To date, only pairwise combinations of Chinese herbal medicine, cupping therapy, and NB-UVB phototherapy for plaque psoriasis have been reported, and the curative effects have been found to differ. In the multi-center, randomized, controlled, single-blinded clinical trial proposed herein, we intend to combine Jueyin granules (JYG) and moving cupping therapy in patients with mild-to-moderate plaque psoriasis, and combine JYG, moving cupping therapy, and NB-UVB phototherapy in patients with severe plaque psoriasis, with the aim of optimizing internal and external TCM treatments and establishing a high level of clinical evidence and treatment norms for the integration of Chinese and Western medicines.