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. 2020 Jan 20;2020(1):CD011628. doi: 10.1002/14651858.CD011628.pub2

Su 2017.

Methods Pilot randomised controlled parallel‐arm trial; within‐participants study
Two centres in China (Shanghai and Huashan)
Period of inclusion: May 2015 to April 2016
Participants Inclusion criteria

  • Clinically and histopathologically diagnosed PPP for at least 3 months

  • Age ≥ 18 years


Exclusion criteria

  • Pregnant or breastfeeding women

  • Use of photosensitising drug

  • Phototherapy or any other treatment for PPP within the last 2 months

  • Photosensitivity

  • Immunosuppressive disease

  • History of melanoma or any other skin cancer


Baseline data: sides were randomised to receive UVA1 (n = 33) or NB‐UVB treatment (n = 33) according to a left‐right randomisation table

  • Male/female: 42/22

  • Mean age (range), years: 46 ± 12 (23 to 68)

  • Mean duration of disease (range), months: 102 ± 81 (4 to 282)

  • PPPASI score (mean): 7.538 ± 2.906; 6.919 ± 1.893

  • Proportion of participants with psoriatic lesions elsewhere: not specified


Withdrawal: 2 dropouts (1 in the UVA1 group discontinued for non‐compliance, and 1 in the NB‐UVB group dropped out for personal reasons)
Interventions Intervention 1
A: UVA1 phototherapy (32 participants)
Intervention 2
B: Narrowband UVB phototherapy (32 participants)
Co‐interventions: none
Duration of treatment: 30 sessions (3 sessions per week)
Outcomes No primary or secondary outcome pre‐specified

  • PPPASI score

  • Adverse reactions
Notes This study was supported by a grant from the Natural Science Foundation of Shanghai Municipal Commission of Health and Family Planning (201640188)
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk Quote: "All patients were randomly assigned to either UVA1 or NB‐UVB treatment according to a left‐right randomisation table"
Comment: probably done
Allocation concealment (selection bias) Unclear risk Comment: not clear
Blinding of participants and personnel (performance bias) 
 All outcomes High risk Comment: no blinding
Blinding of outcome assessment (detection bias) 
 All outcomes High risk Comment: no blinding
Incomplete outcome data (attrition bias) 
 All outcomes Low risk Quote: "one patient of the UVA1 group discontinued for non‐compliance, and one patient of the NB‐UVB group dropped out for personal reason. Therefore, 64 completed the study"
Comment: only 2 dropouts; we know the reasons
Selective reporting (reporting bias) Unclear risk Comment: no protocol and no registration found to guarantee that all planned outcomes are presented in the results