Recommended Oral Antibiotic Regimens for Uncomplicated Cellulitis
For uncomplicated cellulitis, a 5-day course of oral antibiotics targeting β-hemolytic streptococci and methicillin-sensitive Staphylococcus aureus is recommended as first-line therapy, with options including penicillin, amoxicillin, dicloxacillin, or cephalexin. 1
First-Line Treatment Options
Non-Purulent Cellulitis
- Target β-hemolytic streptococci with:
- Duration: 5 days is as effective as 10 days if clinical improvement occurs 3, 1, 4
Purulent Cellulitis
- Empiric coverage for community-acquired MRSA pending culture results:
- Incision and drainage is essential for any residual abscess 1
Combination Coverage Options
When coverage for both streptococci and CA-MRSA is needed:
- Clindamycin alone
- TMP-SMX or tetracycline plus a β-lactam (e.g., amoxicillin)
- Linezolid alone 1
Treatment Duration
- 5 days of antibiotic treatment is sufficient for uncomplicated cellulitis if clinical improvement occurs 3, 1, 4
- Extend treatment if no improvement is seen within 5 days 1
- A randomized controlled trial demonstrated equal efficacy between 5-day and 10-day courses of the same antibiotic (levofloxacin) for uncomplicated cellulitis 4
Special Considerations
Macrolide Resistance
- Macrolide resistance among group A streptococci has increased regionally in the United States 3
- Consider local resistance patterns when selecting antibiotics
Adjunctive Therapy
- Elevation of the affected area promotes gravity drainage of edema and inflammatory substances, hastening improvement 3
- Systemic corticosteroids may attenuate inflammatory reactions and hasten resolution in select adult patients with uncomplicated cellulitis 3
- Anti-inflammatory agents (NSAIDs) may help accelerate resolution of inflammation 6
Treatment Failure Considerations
- If no improvement within 48-72 hours, consider:
Prevention of Recurrence
- Treat underlying conditions that may predispose to infection:
- Tinea pedis
- Venous eczema
- Lymphedema
- Skin trauma 3
- Keep skin well hydrated with emollients to prevent dryness and cracking
- Reduce underlying edema through elevation, compression stockings, or diuretic therapy if appropriate 3
Monitoring and Follow-up
- Patients should be monitored for improvement within 48-72 hours of initiating treatment
- Watch for signs of treatment failure such as increasing erythema, edema, or pain 1
- Patients should complete the full course of antibiotics even if symptoms improve quickly
Remember that cellulitis is primarily caused by β-hemolytic streptococci and Staphylococcus aureus, and empiric therapy should target these organisms unless local resistance patterns or specific risk factors suggest otherwise.