Background: Cellulitis is a common emergency department (ED) presentation. Despite the fact that diagnosis remains relatively straight forward, complexity remains in management in terms of the causative agent and appropriate antibiotic regimen. Though beta-hemolytic Streptococci are the most common causative agents there is increasing prevalence of community acquired methicillin-resistant Staphylococcus aureus (MRSA). Cephalexin has long been used to treat uncomplicated cellulitis because of it’s activity against streptococci and methicillin-sensitive S. aureus (MSSA). Despite the current Infectious Disease Society of America (IDSA) recommendations against routine coverage of MRSA, trimethoprim-sulfamethoxazole (TMP-SMX) is often added to cephalexin (Stephens 2014). While there are other single options for coverage, they either have suboptimal MRSA coverage (i.e. clindamycin and doxycycline) or are more expensive (i.e. linezolid). Without reliable ways to determine which patients need MRSA coverage, it is unclear which patients with uncomplicated cellulitis need to be discharged with MRSA coverage and which will do fine with a single agent.