Criteria & Principles
Patients with nonpurulent cellulitis should be managed with empiric therapy for infection due to beta-hemolytic streptococci and MSSA. Patients with nonpurulent cellulitis and additional risk factors for MRSA should be managed with empiric therapy for infection due to beta-hemolytic streptococci and MRSA.
The clinical isolation rate of a pathogen is <20% in nonpurulent cellulitis.
Treatment
Severity
Mild-Moderate
Mild infection: typical cellulitis/erysipelas with no focus of purulence
- Cephalexin 250-500 mg PO q6h, OR
- Dicloxacillin 250-500 mg PO q6h, OR
- Cefadroxil 500 mg PO q12h
- Severe beta-lactam allergy: clindamycin 300 - 450 PO q6h
- Review the Penicillin Allergy CustomID page (https://www.customid.org/diagnosis-procedure/penicillin-allergy-assessment-po-challenge-penicillin-skin-testing) to verify true allergy
Moderate infection: typical cellulitis/erysipelas with systemic signs of infection
- Cefazolin 2g IV q8h, OR
- Clindamycin 600 mg IV q8h, OR
- Ceftriaxone 1g IV q24h
Severe
Severe infection: patients who have failed oral antibiotic treatment or those with systemic signs of infection, or those who are immunocompromised, or those with clinical signs of deeper infection such as bullae, skin sloughing, hypotension, or evidence of organ dysfunction
Rule out necrotizing process with surgical inspection and debridement
- Vancomycin + piperacillin-tazobactam 3.375g IV q8h extended infusion, OR
- Vancomycin + cefepime 1g IV q6h (MILD penicillin allergy), OR
- Vancomycin + aztreonam 2g IV q8h (SEVERE penicillin allergy)
Severe & Complicated
Necrotizing Infections:
Necrotizing infections (necrotizing fasciitis, Fournier's gangrene, Ludwig's angina) should prompt emergent surgical consultation for souce control. Linezolid (alternative: vancomycin + clindamycin) is recommended in NSTIs for toxin inhibition and empiric MRSA coverage.
- PREFERRED (NO contraindication to linezolid use)
- Standard: linezolid 600mg IV q12h + piperacillin-tazobactam 4.5g IV q8h EI
- Mild PCN allergy: linezolid 600mg IV q12h + cefepime 2g IV q8h EI + metronidazole 500mg IV q12h
- Severe beta-lactam allergy: linezolid 600mg IV q12h + aztreonam 2g IV q8h + metronidazole 500mg IV q12h
- ALTERNATIVE (contraindication to linezolid use)
- Standard: vancomycin + piperacillin-tazobactam 4.5g IV q8h EI + clindamycin 900mg IV q8h
- Mild PCN allergy: vancomycin + cefepime 2g IV q8h EI + metronidazole 500mg IV q12h + clindamycin 900mg IV q8h
- Severe beta-lactam allergy: vancomycin + aztreonam 2g IV q8h + metronidazole 500mg IV q12h + clindamycin 900mg IV q8h
References
Stevens DL, et al. 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; 59: e10-52.