Dreno 1993.

Methods	Randomised, double‐blind Disease control = reduction of blisters, redness & itch > 50% Follow‐up: 10 days (= treatment period)
Participants	57 participants with BP confirmed by IF studies
Interventions	A: 29/29 participants prednisolone (1.16 mg/kg/day). B: 28/28 participants methylprednisolone (1.17 mg/kg/day).
Outcomes	Number of blisters Extent of erythema scale: 0 (absent) to 3 (severe) The intensity of pruritus (itch), scale 0 (absent) to 3 (severe), at days 5 and 10
Notes	Problem: 'scale' for measuring symptoms & signs. Very short study duration
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The study was randomised.
Allocation concealment (selection bias)	Unclear risk	Unclear.
Blinding (performance bias and detection bias) All outcomes	Low risk	Yes: double‐blind. Quote: "Taking into account the difference in presentation between the 2 products, the supply of the products to the participants was made by a person other than the investigator; additionally clinical follow‐up after the end of the study was done by a masked (blinded) investigator." (Translation, page 518)
Incomplete outcome data (attrition bias) All outcomes	Low risk	29/29 evaluated at both time points for prednisolone group. 27/28 evaluated at both times points for the methylprednisolone group. 1 participant dropped out (ceased treatment) after 8 days of treatment, due to a coma unrelated to the treatment (page 519).
Selective reporting (reporting bias)	Low risk	All outcomes (number of blisters, itching, and redness) reported on at 5 and 10 days of treatment.
Other bias	Unclear risk	Short study duration. Non‐validated assessment scales.