To characterise the Emergency Department (ED) prevalence of cellulitis, factors predicting oral antibiotic therapy and the utility of the Clinical Resource Efficiency Support Team (CREST) guideline in predicting patient management in the ED setting, a prospective, cross-sectional study of consecutive adult patients presenting to 3 Irish EDs was performed. The overall prevalence of cellulitis was 12 per 1,000 ED visits. Of 59 patients enrolled, 45.8% were discharged. Predictors of treatment with oral antibiotics were: CREST, Class 1 allocation (odds ratio (OR) 6.81, 95% Cl =1.5-30.1, p=0.012), patient self-referral (OR= 6.2, 95% Cl 1.9- 20.0, p=0.03) and symptom duration longer than 48 hours (OR 1.2, 95% Cl = 1.0-1.5,p=0.049). In conflict with guideline recommendation, 43% of patients in CREST Class 1 received IV therapy. Treatment with oral antibiotics was predicted by CREST Class 1 allocation, self-referral, symptom duration of more than 48 hours and absence of pre-EO antibiotic therapy.