Cell-free DNA Levels in Cellulitis: A Cross-sectional Prospective Study

Cellulitis is a prevalent inflammatory dermatosis caused by bacterial infection that lacks a definitive quantitative biomarker for assessing disease activity and monitoring therapeutic response, leading to diagnostic ambiguity and management challenges. Cell-free DNA (cfDNA), consisting of short nucleic acid fragments released into circulation from necrotic and apoptotic cells, represents a potential objective measure of systemic inflammation. We hypothesized that cfDNA levels would be elevated in patients with cellulitis and correlate with established inflammatory parameters and clinical outcomes. We conducted a cross-sectional prospective study of 36 patients with confirmed cellulitis and 30 healthy controls. Plasma cfDNA levels were quantified at baseline (admission), 72 hours after antibiotic initiation, at discharge, and at 3-week follow-up. We assessed correlations between cfDNA and traditional inflammatory markers, including C-reactive protein (CRP) and white blood cell (WBC) counts, as well as patient-reported pain scores. Patients with cellulitis exhibited significantly elevated plasma cfDNA levels at admission compared with healthy controls. Following antibiotic therapy, cfDNA levels declined rapidly and were positively correlated with reductions in WBCwhite blood cell/neutrophil counts. Higher cfDNA levels were also associated with increased subjective pain scores. These findings suggest that cfDNA may serve as a promising biomarker for the diagnosis of cellulitis and for objectively monitoring treatment efficacy, with potential utility as an objective proxy for pain severity.