Cazzaniga 2014.

Methods	Randomised, within‐patient clinical trial Three centres in Italy Period of inclusion: March 2010 to June 2012
Participants	Inclusion criteria Diagnosis of palmoplantar pustulosis for at least 1 year involving at least 5% of the plantar surface area, symmetrically distributed, with a difference in extension between right and left sides equal ≤ 10% Age 18 to 65 years Exclusion criteria Received any systemic treatment for psoriasis, ultraviolet B phototherapy, or psoralen plus ultraviolet A therapy during the 3 months before inclusion in the study Baseline data: dressing sides were uniformly randomised on a 1:1 basis to sock made of fluorine‐synthetic fibre (17 soles) or sock made of cotton fabric (17 soles) Median age (range), years: 57 (27 to 65) Male/female: 4/13 Duration of condition, median (range): 3 years (1 to 21) Median lesion area (range), cm²: 14 (2.0 to 67.1); 23.5 (2.9 to 68.2) Proportion of participants with psoriatic lesions elsewhere: not specified Withdrawal: 3 participants were lost to follow‐up because of bad compliance; 1 withdrew from the study after the second week for worsening of pathological conditions
Interventions	Intervention A: sock made of fluorine‐synthetic fibre (17 soles) Control Intervention B: sock made of cotton fabric (17 soles) Co‐interventions: topical corticosteroids or vitamin D derivatives Duration of treatment: 4 weeks
Outcomes	Primary outcome Percentage reduction from baseline in lesion areas Secondary outcomes Physician Global Assessment on a 6‐point scale Anchored horizontal 100‐mm visual analogue scale (participant estimation of impact on daily life activities) Global satisfaction (modified visual analogue scale) Adverse events
Notes	This trial was supported by a grant from Lenzi Egisto S.p.A. Clinical trial: NCT01197989
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Dressing sides were uniformly randomised on a 1: 1 basis. Centralised telephone randomisation procedures were adopted" Comment: probably done
Allocation concealment (selection bias)	Low risk	Quote: "Centralized telephone randomisation procedures were adopted, and both investigators and outcomes assessor were blinded to the randomisation rule" Comment: probably done
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "Both socks were tailor‐made by the study sponsor in order to be as similar as possible regarding colour, model and texture of fabric" Comment: patients and personnel were unaware of the socks used
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "Both socks were tailor‐made by the study sponsor in order to be as similar as possible regarding colour, model and texture of fabric. Both investigators and outcomes assessor were blinded to the randomisation rule" Comment: probably done
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "Three patients dropped out of the study for low compliance rate, one after baseline, one after the first week and one after the second week, while one patient withdrew from the study after the second week for worsening of pathological conditions (loss of 23.5% of enrolled patients). An intention‐to‐treat approach was adopted in the primary analysis. In this analysis, patients lost to follow‐up were recovered by the last observation carried forward technique. Intention‐to‐treat analysis was then complemented by per‐protocol analyses, which considered only those patients who completed the study period" Comment: intention‐to‐treat approach was adopted. So, we know how they dealt with missing data
Selective reporting (reporting bias)	Low risk	Comment: the study protocol is available and all of the study’s pre‐specified (primary and secondary) outcomes of interest in the review have been reported in the pre‐specified way