Lessons Learned From a Randomized Controlled Trial of Short-Course Intravenous Antibiotic Therapy for Erysipelas and Cellulitis of the Lower Limb (Switch Trial)

Background The diagnosis of cellulitis is made clinically without a gold standard diagnostic test, and cellulitis has many disease mimics. There is currently no consensus for optimal antimicrobial treatment duration or method of antimicrobial delivery. Methods This was a randomized controlled open-label multicenter trial to determine the safety and efficacy of 24 hours of intravenous (IV) therapy compared with ≥72 hours of IV therapy, both followed by oral therapy to a maximum of 7–10 days’ duration for the treatment of lower limb cellulitis. Results Over 40 months, 80 patients were recruited. Thirty-nine patients were assigned to 24 hours of IV antibiotics and 41 to ≥72 hours of IV antibiotics. The mean duration (range) of IV antibiotics in the 24-hour group was 25.5 (17–40) hours, and in the ≥72-hour group it was 78 (41.5–210) hours. Three patients in the 24-hour arm and 4 patients in the ≥72-hour arm were excluded from the analysis due to withdrawal from the trial. Analysis of the remaining patients revealed that 6 patients (4 in the intervention arm and 2 in the control arm) did not achieve an adequate response to therapy. Only 1 patient experienced self-limiting adverse effects of treatment. Conclusions The noninferiority of short-course IV therapy cannot be determined from this trial. Challenges included resource limitations for recruitment, misdiagnosis, participant withdrawal, and subjective responses to therapy based on visual assessment by treating clinicians. Further studies are needed to determine if short-course IV therapy is a suitable treatment option. Australia Council of Clinical Trials Registry No ACTRN12613001366741.