What is the recommended treatment for cellulitis?

Treatment for Cellulitis

For typical cases of cellulitis without systemic signs of infection, a 5-day course of antibiotics active against streptococci is the recommended treatment. 1

Antimicrobial Selection Algorithm

Mild Cellulitis (No Systemic Signs)

• First-line treatment: Antibiotics active against streptococci 1
  • Penicillin
  • Amoxicillin
  • Dicloxacillin
  • Cephalexin (500 mg every 6 hours orally)
  • Clindamycin (if penicillin allergic)

Moderate Cellulitis (With Systemic Signs)

• Treatment: Systemic antibiotics with consideration for MSSA coverage 1
  • Cefazolin (0.5-1 g every 8 hours IV)
  • Oxacillin/nafcillin (2 g every 6 hours IV)

Severe Cellulitis or High Risk for MRSA

• Treatment: Coverage for both MRSA and streptococci 1
  • Vancomycin (15 mg/kg every 12 hours IV)
  • Linezolid (600 mg every 12 hours)
  • Daptomycin
  • Telavancin
  • Oral options: doxycycline, clindamycin, or SMX-TMP

Special Circumstances

• Severely compromised patients: Broad-spectrum coverage with vancomycin plus either piperacillin-tazobactam or imipenem/meropenem 1

Duration of Therapy

• Standard duration: 5 days 1
• Extend treatment if infection has not improved within 5 days 1
• Recent evidence confirms that 5-6 days of therapy is as effective as longer courses for uncomplicated cellulitis 1, 2

Adjunctive Measures

1. Elevation of affected area to promote drainage of edema and inflammatory substances 1
2. Treatment of predisposing factors such as edema, obesity, eczema, venous insufficiency, and toe web abnormalities 1
3. Consider systemic corticosteroids (prednisone 40 mg daily for 7 days) in non-diabetic adult patients to hasten resolution 1, 3
4. For recurrent cellulitis: Address underlying conditions and consider prophylactic antibiotics for patients with 3-4 episodes per year 1

Hospitalization Criteria

Hospitalize patients with:

• Systemic inflammatory response syndrome (SIRS)
• Altered mental status
• Hemodynamic instability
• Concern for deeper or necrotizing infection
• Poor adherence to therapy
• Severe immunocompromise
• Failure of outpatient treatment 1

Common Pitfalls and Caveats

1. Misdiagnosis: Cellulitis is often confused with conditions like venous stasis dermatitis, contact dermatitis, and lymphedema 4. Ensure proper diagnosis before initiating treatment.

2. MRSA coverage: MRSA is an unusual cause of typical cellulitis. Routine MRSA coverage is unnecessary for uncomplicated, non-purulent cellulitis 1, 4. Reserve MRSA coverage for specific risk factors:

   • Penetrating trauma
   • Evidence of MRSA infection elsewhere
   • Nasal colonization with MRSA
   • Injection drug use
   • Purulent drainage
   • SIRS 1

3. Cultures: Blood or skin cultures are not routinely recommended for typical cellulitis 1. Reserve cultures for:

   • Patients with malignancy on chemotherapy
   • Neutropenia
   • Severe cell-mediated immunodeficiency
   • Immersion injuries
   • Animal bites 1

4. Interdigital spaces: In lower-extremity cellulitis, carefully examine interdigital toe spaces and treat any fissuring, scaling, or maceration to prevent recurrence 1

5. Recurrent cellulitis: For patients with recurrent episodes, identify and treat predisposing factors. Consider prophylactic antibiotics for those with 3-4 episodes per year 1

By following this evidence-based approach to cellulitis treatment, clinicians can effectively manage this common infection while minimizing unnecessary antibiotic use and preventing complications.