Ludvigsen 1983.

Methods	Study type: individual RCT Randomisation method: computer‐based randomisation Blinding: double‐blind Intention‐to‐treat analysis used: not used
Participants	Inclusion criteria of the trial Seborrhoeic dermatitis of the scalp Exclusion criteria of the trial Not reported Number of randomised participants: 30 in total (betamethasone N = 15, hydrocortisone N = 15, but 1 of the participants in the latter group proved to be too young to be included, and the results were not used) Number of dropouts: 1 participant was excluded after randomisation because of their young age (not considered a dropout); 1 participant was lost to follow up (considered a dropout, 3%) Sex: 17 males, 12 females Mean age (range): 49.9 (19 to 82) years Country: Denmark
Interventions	Treatment Betamethasone 0.05% lotion, applied to the scalp twice daily for 3 weeks Comparator/s Hydrocortisone 0.1%, applied to the scalp twice daily for 3 weeks
Outcomes	Erythema, scaling, follicular papule formation, crusting, itching, and burning/local irritation scores (scale 0 to 3) Total clearance evaluated by participants and clinician Adverse events
Notes	Participants used drugs for 3 weeks or until complete healing. Outcomes were assessed at 3 weeks. Scores were calculated only for those who had the symptom
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "A computer programme was used to give the randomization code, which was stratified into blocks of 10 with a restriction against more than three successive patients receiving the same therapy"
Allocation concealment (selection bias)	Unclear risk	Quote: "randomization code, which was stratified into blocks of 10 with a restriction against more than three successive patients receiving the same therapy"
Similarity of the study groups (selection bias)	Low risk	Quote: "No statistically significant difference in patient classification of mean age, sex distribution and initial symptom score distribution was found between the two treatment groups but there was a numerically lower mean age in the HCB‐treated group" 44 years versus 56 years
Blinding of participants (performance bias)	Unclear risk	The study was "double‐blind"; this was not reported in detail. The participants were given Locoid® or Diproderm®, and it was not reported if the packages were blinded
Blinding of care providers (performance bias)	Unclear risk	Whilst the study was reported to be double‐blind, it was not clear who was blinded
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Whilst the study was reported to be double‐blind, it was not clear who was blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	The dropout rate was small
Selective reporting (reporting bias)	Unclear risk	Predefined outcomes were reported, but they were assessed as scores only for those who had the symptom
Other bias	Low risk	No other bias was identified