Treatment for Cellulitis
First-line treatment for non-purulent cellulitis is cephalexin 500 mg orally four times daily for 5-6 days. 1
Antibiotic Selection
First-line options:
- Cephalexin 500 mg orally four times daily (5-6 days) 1
- Dicloxacillin 500 mg orally four times daily (5-6 days) 1
- Amoxicillin-clavulanate 875/125 mg orally twice daily (5-6 days) 1
For penicillin-allergic patients:
- Clindamycin 300-450 mg orally three times daily (5-6 days) 1
- Trimethoprim-sulfamethoxazole (TMP-SMX) (5-6 days) 1
- Doxycycline or minocycline (5-6 days) 1
- Linezolid 600 mg orally twice daily (more expensive option) 1, 2
MRSA Considerations
If MRSA is suspected:
- Continue cephalexin for streptococcal coverage AND
- Add TMP-SMX 160mg/800mg twice daily 1
Treatment Duration
- 5-6 days is sufficient if clinical improvement occurs 1
- This shorter duration is supported by research showing 5-day courses are as effective as 10-day courses for uncomplicated cellulitis 3
Supportive Care Measures
- Elevate the affected area to reduce edema and promote drainage of inflammatory substances 1
- Some evidence suggests adding an anti-inflammatory agent (like ibuprofen) may hasten resolution of inflammation, though this is not part of standard guidelines 4
Monitoring Response
- Monitor daily for improvement
- Reassess diagnosis if no improvement after 48-72 hours 1
- Be aware of local resistance patterns and consider alternative therapy if necessary 1
Abscess Management
- If an abscess is present, incision and drainage is the primary treatment 1
- For simple abscesses, antibiotics may not be needed after adequate drainage 1
Indications for Hospitalization and IV Antibiotics
Hospitalize patients with:
- Systemic inflammatory response syndrome (SIRS)
- Altered mental status
- Hemodynamic instability
- Consider vancomycin as primary option for MRSA coverage in these cases 1
Prevention of Recurrence
- Address predisposing factors such as:
Common Pitfalls to Avoid
- Misdiagnosis (conditions like venous insufficiency, eczema, deep vein thrombosis, and gout are frequently mistaken for cellulitis) 6
- Overuse of broad-spectrum antibiotics for typical non-purulent cellulitis
- Unnecessary MRSA coverage for typical cellulitis
- Inadequate duration of therapy
- Failure to elevate the affected area
- Overlooking underlying conditions 1
The evidence strongly supports a 5-6 day course of cephalexin as first-line therapy for non-purulent cellulitis, with appropriate alternatives for penicillin-allergic patients or when MRSA is suspected. Elevation of the affected area and addressing underlying risk factors are essential components of management.