The proposed study was designed as a prospective multicentre, two-arm parallel group, single-blind RCT with patients with plaque psoriasis randomly assigned to either the treatment group (moving cupping) or the placebo group (sham moving cupping). Eligible participants will receive 4 weeks of treatment and a total of 8 weeks of follow-up (Figure 1).
Patient and public involvement
Neither patients nor the public were involved in the design of the RCT.
We plan to recruit 110 patients with plaque psoriasis for the present study. Recruitment will take place in the Yueyang Hospital of Integrated Traditional Chinese and Western Medicine (Shanghai, China), Shaanxi Traditional Chinese Medicine Hospital (Shaanxi, China), First Affiliated Hospital of Heilongjiang University of Traditional Chinese Medicine (Heilongjiang, China), The Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine (Jiangxi, China), Hospital of Traditional Chinese Medicine, Xinjiang Medicine University (Xinjiang, China), and Shijiazhuang Hospital of Traditional Chinese Medicine (Shijiazhuang, China). Eligible recipients will be recruited via social media, word of mouth, and dermatology out-patient clinics at local hospitals. Patients who are willing to join the clinical trial will receive study information and consent forms. The consent forms must be signed before the patients are included in the study. Figure 1 presents a flowchart of participant enrolment and analysis through the course of the trial. All consent and/or assent will be obtained by the researchers prior to the recipients’ participation in the trial. All potential and enrolled recipients’ personal information will be recorded and kept in a secure folder and made accessible only to the researchers to protect their privacy.
All patients who are diagnosed with plaque psoriasis will undergo laboratory blood testing before inclusion, including a complete blood cell count, liver function test, renal function test, and pregnancy test. Additionally, routine urine tests, vital sign monitoring, and physical examination will be performed (Figure 2).
- Meet the diagnostic criteria for plaque psoriasis; 2. Skin lesions involve ≤10% BSA (the lesions are mainly located on the torso/limbs, palm/sole, or face/scalp, with the vulva area being unaffected); 3. Aged 18-65 years; and 4. Provide consent to participate in the study and sign the informed consent form.
- Any clinically active skin diseases other than moderate to severe psoriasis vulgaris that might confound or influence the study aim; 2. Patients who received any systemic treatments within 4 weeks before the baseline visit (e.g. drugs for other studies, immuno-suppressive drugs, biologics); 3. Patients who received topical treatment within 2 weeks before the baseline visit (e.g. corticosteroids, ultraviolet-light therapy including sunbathing); 4. Patients with an active infectious disease that is difficult to control; 5. Patients with a history of severe systemic disease, an alanine aminotransferase or aspartate transaminase level greater than 1.5 times that of the average; any of the main routine blood indices (white blood cell count, red blood cell count, haemoglobin level, platelet count) lower than the normal limit, or other laboratory abnormalities; 6. Family history of cancer-prone patients; 7. Immunocompromised patients who may experience skin allergies or infection with moving cupping therapy; 8. Pregnant or lactating women; 9. Patients with a history of alcohol or drug abuse; 10. Patients with a history or family history of serious mental illness.
Randomisation, allocation, and blinding
After obtaining informed consent, patients will be randomised in a 1:1 ratio to either the moving cupping group or the placebo group. To ensure allocation concealment, central randomisation will be applied, and the random allocation sequence will remain concealed from the recruiting dermatologist. Due to the nature of moving cupping, it is not possible to blind the operating doctor involved in applying the treatment. To ensure blinding, we will use a placebo-cup to simulate the treatment of moving cupping and shield the patient's eyes with a black opaque eye mask. The treatment device will be of the same size and material, and the treatment method will maintain a consistent treatment frequency and intensity, but with no adsorption force. The operating doctor will not participate in the statistical analysis, and the treatment plan and grouping will be known only by the statistical analyst.
Moving cupping intervention
Cup: Transparent glass texture. Different types of cups will be selected according to the patient’s skin lesions and related conditions (Figure 3).
Standardised manipulations of moving cupping: (1) First, apply Vaseline to the skin lesion area. (2) Hold a 95% ethanol-soaked cotton ball with tweezers, and hold the cup with the face down. After the cotton ball is ignited, immediately move the ball down inside the cup and remove it, and then quickly place the cup on the skin lesion area. (3) After using the cup to absorb the skin lesion area, hold the cup body in one hand and push and pull the cup along the specified route while applying light force, such that the skin of the treatment area turns purple in colour. (4) Apply even force when pushing the cup to prevent the cup from falling off due to air leakage. (5) Repeat on the skin lesion area 30 times, changing the cup five times per push and pull, with an interval of no more than 10 s, once every other day for 4 weeks.
Moving cupping placebo
Take a special perforated cup, select the same material as the intervention group and use the same manipulation method. Because of the perforated design, the fire cannot burn the air in the cup, so it can't form a negative pressure adsorption force. Thus, it simulates the form of moving cupping therapy without the therapeutic effect of moving cupping (Figure 3).
- Increase moisturising of the skin: As a basic treatment, the use of a moisturiser at all times is a must. The moisturiser should mainly be applied to the skin areas that are free of erosion and exudation, as well as the dry non-lesion areas. A soft, fragrance-free moisturiser should be used, and Yuze moisturiser will be recommended to patients for sensitive dry skin.
- Standard bath: Generally, patients should rinse quickly with warm water (35–39 °C) for approximately 5 min, once per day. Moisturiser should be applied within 2 min of bathing to avoid dehydration of the epidermis. In addition, the use of alkaline detergents to clean the skin should be avoided.
- Avoidance of induced and aggravated factors: Some patients may have food allergies. Once food allergies are identified, such foods should be avoided to prevent inducing or aggravating the condition.
- Maintain a reasonably healthy lifestyle: Patients should avoid staying up late and becoming over-stressed. Spicy, irritating foods should be avoided, and appropriate exercise should be undertaken. Patients should try to maintain normal bowel movements.
- Adherence to reasonable treatment: Doctors and patients should conduct full communication and establish good mutual trust. Patients should adhere to reasonable treatment and care to achieve long-term relief.
Patient’s vital signs and disease severity will be monitored by means of physical examination, biochemical examination, and different evaluation indices before treatment. Data from the above measures will be used as baseline moving cupping therapy data.
Examination during the interview
All patients will be interviewed at weeks 1, 2, 3, and 4 during the treatment. During weeks 1, 2, 3, and 4 of treatment, the psoriatic lesions will be measured by the PASI, PGA, BSA, and TCMSSS, and self-evaluation using the DLQI, PR-QoL, and VAS will be used to assess quality of life, psychological status, and degree of pruritus, respectively. In addition, in weeks 6 and 8 of the follow-up period, the PASI, PGA, BSA, and VAS will be recorded again to evaluate the efficacy of moving cupping. Possible adverse events and combined medications should be accurately recorded at all of the above time points.
Examination during follow-up
All patients will be recalled for a follow-up session at weeks 6 and 8 after treatment. For each session, the treatment effects will be assessed using the PASI, PGA, BSA, and VAS.
PASI: Incorporates the extent of psoriasis at four anatomic sites by evaluating signs of erythema, scale, and elevation. PASI scores range from 0 to 72. The primary outcome of the RCT is the proportion of patients with a ≥75% reduction in PASI scores compared to baseline at the 4-week follow-up visit. 
The secondary parameters of this study include the following:
- PGA: The PGA is scored on a five-point scale, reflecting the overall degree of erythema, infiltration, and desquamation across all psoriatic lesions. 
- BSA: The BSA involved in psoriasis is estimated by fingerprinting, wherein the entire palm of the patient represents approximately 1% of the total BSA. The number of handprints on psoriatic skin on a body part is used to determine the extent to which the body part is affected by psoriasis (%). 
- DLQI: The DLQI is a participant-reported questionnaire used to measure the health-related quality of life of adults with skin diseases. Scores range from 0 to 30, with a higher score indicating a greater impact on the participant’s quality of life. 
- PR-QoL: The PR-QoL is used to assess the impact of psoriasis on an individual’s social life. Scores range from 0 to 25, with a higher score indicating a greater impact on the participant's social life. 
- VAS: The VAS is used to measure lesion pruritus from 0 to 100 mm at each visit (with 0 indicating no pruritus and 100 indicating maximum pruritus). 
- TCMSSS: According to the different TCM syndromes of patients, comprehensive evaluation will be carried out from tongue-condition, pulse-condition, and skin, etc. 
All participants will be advised to remain under supervision in the clinical research unit for 15 min after treatment. In addition, participants’ data will be monitored by the research team throughout the study for any adverse events, in particular, skin damage or potential allergies. All potential adverse events will be recorded. If any participant experiences an adverse effect as a result of trial participation, they will receive free treatment and compensation accordingly. If any concerns are identified during screening or clinical assessment of the participants, further clinical evaluation and/or investigation will be immediately undertaken. If concerns are identified during the study, the participant will be withdrawn if this is believed to be in their best interest.
The sample size of the current trial was calculated based on the formula: N = 4 (Z𝐚/2 + Z𝛃 )2 ( ) / (P0–P1 )2.  The inspection level (α) was set at 0.05, the test power was 0.8, then 1-β=1-0.1=0.8. According to the clinical trial results and data analysis of recently published articles,  the study group PASI-50 reached 75%, the control group reached 35.3%, 42 participants will be required for each group. Given a loss to follow-up rate of approximately 30%, we expect to require 55 participants for each group. As a result, this trial will require at least 110 participants in its current setup.
The recruitment began in August 2019, and the intervention period will end in December 2020. Figure 2 provides the study schedule of enrolment, intervention, and assessment.
Data collection and management
Including data records, data recording requirements, medical record review, data reporting, data monitoring, data inspection, and blinded method implementation audits are entrusted to the Nanjing Ningqi Medical Technology Co., Ltd. Data Management Centre.
- Statistical analysis plan and statistical software: After the test plan is determined, the statistical professional will be responsible for formulating a statistical analysis plan in consultation with the main investigator. Analysis will be performed using SAS statistical software.
- Data management and statistical analysis: Data management, selection of analytical data sets, statistical analysis content, and statistical analysis methods will be based on the data network platform designed by Nanjing Ningqi Medical Technology Co., Ltd. Data Management Centre and will be commissioned by the centre for third-party statistics. The measurer will be blinded to the results.
The possibility of loss to follow-up was considered and calculated as a part of the study’s sample size estimation. In addition, we will account for other types of randomly missing data by treating dropouts as non-success or non-survival using the intention-to-treat principle.