The Natural History of Antibiotic-Treated Lower Limb Cellulitis: Analysis of Data Extracted From a Multicenter Clinical Trial.

Background: Although cellulitis is a relatively common skin infection, there remains uncertainty about management, particularly the length and route of antimicrobials required. Further information on the symptomatology and biomarker changes associated with cellulitis over time would guide clinicians and patients as to the expected natural history. Methods: We extracted data from a randomized clinical trial (NCT01876628) of clindamycin as adjunctive therapy in cellulitis to illustrate the evolution of local parameters (pain, swelling, local erythema, and warmth) and the resolution of biomarkers over time. Results: Data from 247 individuals with mild to moderate unilateral lower limb cellulitis, who attended at least 1 face-to-face interview following recruitment, were used to examine response dynamics. Although there was a local improvement in swelling, warmth, erythema, and pain by day 5 compared with baseline, some individuals still had evidence of local inflammation at 10 days. Most biomarkers demonstrated a return to normal by day 3, although the initial fall in albumin only returned to baseline by day 10. Conclusions: Although there was initial resolution, a significant number of individuals still had local symptoms persisting to day 10 and beyond. Clinicians can use these data to reassure themselves and their patients that ongoing local symptoms and signs after completion of antibiotic treatment do not indicate treatment failure or warrant extension of the initial antibiotic treatment or a change in antibiotic class or mode of administration.