From the Guidelines
For typical cases of cellulitis without systemic signs of infection, the best antibiotic is one that is active against streptococci, such as cephalexin or dicloxacillin. The choice of antibiotic should be based on the severity of the infection and the presence of systemic signs of infection 1.
Key Considerations
- For patients with systemic signs of infection, coverage against MSSA may be included 1.
- In cases of penetrating trauma, evidence of MRSA infection, or severe infection, vancomycin or another antimicrobial effective against both MRSA and streptococci is recommended 1.
- The recommended duration of antimicrobial therapy is 5 days, but treatment should be extended if the infection has not improved within this time period 1.
Treatment Options
- Cephalexin (500 mg orally four times daily) or dicloxacillin (500 mg orally four times daily) are suitable options for mild to moderate cellulitis.
- For patients with penicillin allergies or suspected MRSA, clindamycin (300-450 mg orally four times daily) or trimethoprim-sulfamethoxazole (1-2 double-strength tablets twice daily) may be considered.
- In severe cases requiring hospitalization, intravenous antibiotics such as cefazolin, nafcillin, or vancomycin may be necessary 1.
Additional Measures
- Elevation of the affected area and treatment of predisposing factors, such as edema or underlying cutaneous disorders, are recommended 1.
- Outpatient therapy is recommended for patients who do not have SIRS, altered mental status, or hemodynamic instability 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Antibiotic Options for Cellulitis
- The majority of non-purulent, uncomplicated cases of cellulitis are caused by β-hemolytic streptococci or methicillin-sensitive Staphylococcus aureus, and appropriate targeted coverage of this pathogen with oral antibiotics such as penicillin, amoxicillin, and cephalexin is sufficient 2.
- Antibiotics with activity against community-associated MRSA, such as trimethoprim-sulfamethoxazole and clindamycin, are preferred empiric therapy for outpatients with cellulitis in the community-associated MRSA-prevalent setting 3.
Route of Antibiotic Administration
- There is no evidence to support the superiority of intravenous antibiotics over oral antibiotics for the treatment of cellulitis 4, 5, 6.
- Patients who received only oral therapy were more likely to have improved at day 5 compared with those given at least a single dose of intravenous therapy 4.
Duration of Antibiotic Therapy
- There is no association between the duration of antibiotic therapy and outcome as measured at day 10 and day 30 4.
- Treatment duration of longer than 5 days was not supported by evidence 5, 6.
Factors Associated with Treatment Failure
- Factors associated with treatment failure include therapy with an antibiotic that was not active against community-associated MRSA and severity of cellulitis 3.