What is the recommended treatment for cellulitis?

Treatment of Cellulitis

For typical cases of cellulitis without systemic signs of infection, an antimicrobial agent active against streptococci is recommended for 5 days, with treatment extension if the infection has not improved within this time period. 1, 2

Classification and Initial Assessment

• Severity classification:

  • Mild: No systemic signs of infection
  • Moderate: Systemic signs of infection present
  • Severe: SIRS, altered mental status, or hemodynamic instability

• Risk factors for MRSA to assess:

  • Penetrating trauma
  • Evidence of MRSA infection elsewhere
  • Nasal colonization with MRSA
  • Injection drug use
  • Systemic inflammatory response syndrome (SIRS)
  • Recent antibiotic use in previous 4-6 weeks 2

Antibiotic Treatment Recommendations

Mild Cellulitis (Outpatient)

• First-line: Antimicrobial agent active against streptococci 1
  • Penicillin VK 250-500 mg orally every 6 hours (for facial cellulitis) 2
  • Cephalexin 500 mg 3-4 times daily 2

Moderate Cellulitis

• First-line: Consider coverage for both streptococci and MSSA 1
  • Amoxicillin-clavulanate 875/125 mg twice daily orally 2
  • Clindamycin 300-450 mg orally three times daily 2

Severe Cellulitis (Inpatient)

• First-line: Vancomycin 15-20 mg/kg IV every 8-12 hours (covers both MRSA and streptococci) 2
• Alternative options:
  • Cefazolin 1-2 g IV every 8 hours
  • Nafcillin/oxacillin 1-2 g IV every 4-6 hours 2

For Severely Compromised Patients

• Combination therapy: Vancomycin plus piperacillin-tazobactam or imipenem/meropenem 1, 2

Treatment Duration

• Standard duration: 5 days 1, 2
• Extend treatment if infection has not improved within 5 days 1, 2

Adjunctive Measures

1. Elevation of the affected area to reduce swelling 1, 2
2. Treatment of predisposing factors such as edema or underlying cutaneous disorders 1, 2
3. Examination of interdigital toe spaces in lower-extremity cellulitis to treat fissuring, scaling, or maceration 1, 2
4. Consider systemic corticosteroids (prednisone 40 mg daily for 7 days) in non-diabetic adult patients 1, 2

Hospitalization Criteria

Hospitalization is recommended if:

• Concern for deeper or necrotizing infection
• Poor adherence to therapy
• Infection in severely immunocompromised patient
• Outpatient treatment is failing
• SIRS, altered mental status, or hemodynamic instability present 1, 2

Transition from IV to Oral Therapy

• Switch to oral therapy after clinical improvement with IV antibiotics
• Maintain the same antimicrobial spectrum when transitioning 2

Prevention of Recurrent Cellulitis

• Identify and treat predisposing conditions:

  • Edema
  • Obesity
  • Eczema
  • Venous insufficiency
  • Toe web abnormalities 1, 2

• For patients with 3-4 episodes per year: Consider prophylactic antibiotics

  • Oral penicillin or erythromycin twice daily for 4-52 weeks
  • Intramuscular benzathine penicillin every 2-4 weeks 1

Special Considerations

• Blood cultures are not routinely recommended but should be obtained in patients with malignancy on chemotherapy, neutropenia, severe cell-mediated immunodeficiency, immersion injuries, and animal bites 1
• Patients who have received antibiotics in the previous 4-6 weeks should be given an alternative class or higher-dose regimen 2
• Immunocompromised patients may require broader coverage and longer duration of therapy 2