What is the treatment for cellulitis?

Treatment of Cellulitis

For uncomplicated cellulitis, first-line treatment consists of oral antibiotics targeting β-hemolytic Streptococcus and methicillin-sensitive Staphylococcus aureus (MSSA), such as dicloxacillin (500 mg 4 times daily) or cephalexin (500 mg 4 times daily) for 5-6 days. 1

Antibiotic Selection

Oral Antibiotics for Outpatient Treatment

• First-line options (for non-purulent cellulitis):

  • Cephalexin: 500 mg 3-4 times daily for 5-6 days 1
  • Dicloxacillin: 500 mg 4 times daily for 5-6 days 1
  • Amoxicillin-clavulanate: 875/125 mg twice daily for 5-6 days 1

• For penicillin-allergic patients:

  • Clindamycin: 300-450 mg 3 times daily for 5-6 days 1

MRSA Considerations

• MRSA coverage is generally not recommended for standard non-purulent cellulitis 2
• Consider MRSA coverage only with specific risk factors:
  • Athletes, children, men who have sex with men, prisoners
  • Military recruits, residents of long-term care facilities
  • Prior MRSA exposure or intravenous drug use 3
  • Options include: Doxycycline, TMP-SMX, or clindamycin 1

Inpatient Management

For severe infections requiring hospitalization:

• Vancomycin: 15 mg/kg IV every 12 hours 1
• Linezolid: 600 mg IV/PO every 12 hours 1

Treatment Duration and Monitoring

• Standard duration: 5-6 days for uncomplicated cellulitis 1, 3
• Extend treatment if symptoms haven't improved
• Reassess diagnosis if no improvement after 72 hours 1
• Obtain blood cultures before starting antibiotics in severe cases 1
• Culture any wound drainage or abscess material to guide therapy 1

Special Populations

• Pediatric patients: Avoid doxycycline in children under 8 years due to risk of dental staining 1
• Pregnant patients: Avoid doxycycline; use alternative antibiotics 1
• Patients with renal impairment: Adjust dosing accordingly 1

Adjunctive Therapy

Some evidence suggests that adding an anti-inflammatory agent may hasten resolution of cellulitis. In one study, adding ibuprofen 400 mg every 6 hours for 5 days to antibiotic therapy led to faster regression of inflammation and complete resolution of cellulitis 4. However, this is not yet part of standard guidelines and should be considered experimental.

Prevention of Recurrence

• Address predisposing factors 3
• Improve hygiene practices 1
• Consider decolonization for recurrent infections 1
• Recommend daily change of socks and careful drying between toes after showers 1

Common Pitfalls and Caveats

1. Misdiagnosis: Cellulitis can be confused with non-infectious conditions like venous stasis dermatitis, contact dermatitis, eczema, and lymphedema 2. Careful assessment is crucial.

2. Unnecessary broad-spectrum antibiotics: Research shows no benefit to using broad-spectrum antibiotics for uncomplicated cellulitis compared to narrow-spectrum options 5. Stick with targeted therapy against Streptococcus and MSSA unless specific indications for broader coverage exist.

3. Failure to drain purulent collections: Any abscess or purulent collection should be drained as part of treatment 6.

4. Inadequate follow-up: Patients should follow up within 2-3 days of discharge to ensure improvement 1.

5. Missing underlying complications: Consider deeper infection, bacteremia, or immunocompromise if standard treatment fails 3.