Ortonne 2011.

Methods	Study type: individual RCT Randomisation method: "central computed randomization list, block‐size of 4" Blinding: "blinded investigators" Intention‐to‐treat analysis used: yes
Participants	Inclusion criteria of the trial Adults (18 years or more) with moderate or severe scalp seborrhoeic dermatitis Exclusion criteria of the trial Pregnancy or lactating state Women planning pregnancy HIV positivity Number of randomised participants: 326 in the whole study; we used only the results of the clobetasol group (N = 82) and the ketoconazole group (N = 80) Number of dropouts: 12 (7%) at "end of study" Sex: 88 males, 74 females Age (mean): clobetasol arm = 44.9 years, ketoconazole arm = 44.7 years Country: Belgium, France, Germany, Mexico, South Korea
Interventions	Treatment Treatment phase: clobetasol propionate shampoo 0.05%, applied for 15 minutes on dry scalp twice weekly for 28 days Comparator/s Treatment phase: ketoconazole shampoo 2%, applied for 5 minutes on wet scalp twice weekly for 28 days. (In both arms followed by maintenance phase: ketoconazole once weekly; and follow‐up phase: no active treatment, only mild non‐medicated shampoo). (The study had 2 other arms: clobetasol and ketoconazole alternating or clobetasol four times weekly alternating with ketoconazole)
Outcomes	Total severity score (mean change from baseline) Erythema, scaling, and pruritus severity scores (0 to 3 each, expressed as change from baseline and not in exact numbers) Extent index (extent of scalp involved (0 = less than 10% to 4 = more than 70%)
Notes	Only the results for the clobetasol propionate only, and the ketoconazole only, and for the treatment phase are used in the analyses The results for the outcomes were expressed in a way not relevant for the review; therefore, we could use only information for adverse events
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "randomized in a 1:1:1:1 ratio by a designated statistician (using a central computed randomization list that generated treatment numbers in a block‐size of 4)"
Allocation concealment (selection bias)	Unclear risk	This was not reported clearly
Similarity of the study groups (selection bias)	Low risk	Quote: "The demographic and baseline disease characteristics were similar among the four groups"
Blinding of participants (performance bias)	High risk	The participants were not blinded
Blinding of care providers (performance bias)	High risk	The care providers were not blinded
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The investigator was blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	The dropout rate was acceptable
Selective reporting (reporting bias)	Low risk	Predefined outcomes were reported
Other bias	Unclear risk	4 out of 8 authors were affiliated to the pharmaceutical industry