Highton 2011.

Methods	This was a within‐patient RCT in which 1 side of an anatomical site was treated, and the other received no treatment There was a 4‐week treatment period followed by a 12‐month observation phase
Participants	The trial randomised 18 participants with a clinical diagnosis of HS with moderate to severe disease, defined as Hurley stage II or III Participants were required to have bilateral disease in an affected region, and overall, there was no significant difference in disease severity at the control and intervention sites at baseline (P value = 0.31, paired t test). However, information was not provided regarding whether disease severity was comparable on both sides of an affected region for individual participants Disease locations were axillary (12 participants), groin (4 participants), and inframammary (2 participants). 1 participant with inframammary disease dropped out after a single treatment
Interventions	Left and right sides of a single anatomical location were randomised in a 1:1 ratio: untreated control side intense pulsed light, twice per week for 4 weeks (420 nm; fluence: 7 to 10 J/cm2; pulse width: 30 to 50 msec) using a Harmony Laser
Outcomes	Primary outcome Not specified Secondary outcome Overall participant satisfaction with treatment recorded on a Likert scale: worse, unchanged, fair, good, or excellent on a single occasion (the timing was not stated) Sartorius scale (original) score measured immediately post‐treatment and at 3, 6, and 12 months later and reported as a percentage change from baseline
Notes	The publication gave only pooled results for all anatomical locations, but following correspondence, the authors provided a breakdown based on the site of involvement. The trial authors declared no financial conflicts of interest
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The paper provided no details ‐ "patients were randomised"
Allocation concealment (selection bias)	Unclear risk	The paper provided no details
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and personnel were unblinded
Blinding of outcome assessment (detection bias) All outcomes	High risk	Detection bias was low risk for the Sartorius score – the outcome assessor was not the treating clinician and was blinded to treatment allocation. Scoring was repeated from photographs by 2 additional blinded assessors. The trial was high risk for participant satisfaction; participants were unblinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	Only 1 participant dropped out of the study, due to treatment‐related pain
Selective reporting (reporting bias)	Unclear risk	The study was not registered prospectively
Other bias	Low risk	We found no other significant bias