Cellulitis when not associated with abscess or purulence is more likely to be caused by group A streptococcus(GAS) or other streptococci (Group C and Group).
Cellulitis is commonly caused by GAS and Staphylococcus aureus. A non-purulent infection suggests streptococci are more likely to be the etiology. In the absence of SIRS, MRSA colonization, or penetrating trauma, options directed at GAS are appropriate including:
Penicillin VK (No S aureus coverage)
Cephalexin (Also covers MSSA)
Clindamycin (Also provides MSSA and MRSA coverage)
TMP/SMX is an option for suspected Staphylococcal skin and soft tissue infections but may be less effective for GAS.
Stevens DL, Bisno AL, Chambers HF, Dellinger EP, Goldstein EJ, Gorbach SL, Hirschmann JV, Kaplan SL, Montoya JG, Wade JC; Infectious Diseases Society of America. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014 Jul 15;59(2):e10-52. PMID: 24973422
Bruun T, Oppegaard O, Kittang BR, Mylvaganam H, Langeland N, Skrede S. Etiology of Cellulitis and Clinical Prediction of Streptococcal Disease: A Prospective Study. Open Forum Infect Dis. 2015;3(1):ofv181. Published 2015 Nov 25. https://pubmed.ncbi.nlm.nih.gov/26734653/