Kremer 1991.

Methods	A randomised controlled, open‐label, parallel‐group trial
Participants	1. Setting: the trial was conducted in an outpatient (Table 2) setting in northern Israel. The recruitment process of participants was NR 2. Number of participants randomised: 40 3. Sex (men/women): 14/18 (8 participants were lost to follow‐up and their details are NR) 4. Mean age (range): treatment group‐ 63.2 (42 ‐ 75), control group‐ 65.5 (32 ‐ 75) 5. Area of body involved: leg. 2 participants from the control group suffered upper extremity infections 6. Number of episodes of cellulitis prior to intervention: ≥ 2
Interventions	Study groups: Oral erythromycin base 250 mg X 2/d (3 participants changed treatment to penicillin V‐K 250 mg X 2/d due to nausea and vomiting) No treatment except for local treatment Concomitant treatment: local antifungal treatment for tinea pedis Duration of treatment: 18 months Follow‐up:during treatment phase‐monthly, after treatment phase‐ NR
Outcomes	1. The number of participants with repeat episodes of cellulitis 2. The number of repeat episodes of cellulitis 3. The number of participants requiring hospitalisation 4. The number of adverse drug reactions
Notes	Criteria for diagnosis of cellulitis: NR. Comment: the report mentioned that during follow‐up participants with "a relapse" came to the clinic and were treated according to "clinical findings" Funding source and Declaration of interest: NR.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The paper did not provide details
Allocation concealment (selection bias)	Unclear risk	The paper did not provide details
Blinding of participants and personnel (performance bias) All outcomes	High risk	This was an open‐label study
Blinding of outcome assessment (detection bias) All outcomes	High risk	This was an open‐label study
Incomplete outcome data (attrition bias) All outcomes	High risk	8 participants were lost to follow‐up (20% of participants in the study) and the paper did not detail to which groups they were assigned; we conducted a 'per protocol' analysis
Selective reporting (reporting bias)	Unclear risk	There was insufficient information
Similarity of groups at baseline (baseline imbalance bias)	Low risk	Baseline characteristics were reported and balanced (Table 1 in the article).
Early termination (early stopping bias)	High risk	Quote: "After I8 months' follow‐up the differences between the two groups were dramatic, and led us to conclude the study" Comment: the study was terminated based on results and did not report sample size calculation, formal interim analysis or a formal stopping rule
Other bias	Low risk	No other sources of potential bias were found