What is the recommended management for cellulitis?

Management of Cellulitis

For uncomplicated cellulitis, a 5-day course of antibiotics active against streptococci is recommended as first-line therapy, with extension only if the infection has not improved within this time period. 1

Diagnosis

Cellulitis is a bacterial infection of the deep dermis and subcutaneous tissue, presenting with:

• Expanding erythema
• Warmth
• Tenderness
• Swelling

Diagnostic workup:

• Cultures of blood, tissue aspirates, or skin biopsies are not routinely recommended for typical cases 1
• Blood cultures should be obtained in patients with:
  • Malignancy
  • Severe systemic features (high fever, hypotension)
  • Unusual predisposing factors (immersion injury, animal bites)
  • Neutropenia
  • Severe cell-mediated immunodeficiency 1

Antibiotic Therapy

First-line treatment (typical cellulitis):

• Antibiotic active against streptococci 1
• Suitable oral options include:
  • Penicillin
  • Amoxicillin
  • Amoxicillin-clavulanate
  • Dicloxacillin
  • Cephalexin
  • Clindamycin 1

Duration:

• 5 days of antimicrobial therapy is as effective as a 10-day course if clinical improvement has occurred by day 5 1, 2
• Treatment should be extended if the infection has not improved within this period 1

MRSA considerations:

• MRSA is an unusual cause of typical cellulitis 1
• Coverage for MRSA should be considered in cellulitis associated with:
  • Penetrating trauma (especially from illicit drug use)
  • Purulent drainage
  • Concurrent evidence of MRSA infection elsewhere
  • Nasal colonization with MRSA
  • Injection drug use
  • Systemic inflammatory response syndrome (SIRS) 1

Parenteral therapy indications:

• Severely ill patients
• Patients unable to tolerate oral medications
• Options include:
  • Nafcillin
  • Cefazolin
  • Clindamycin or vancomycin (for patients with life-threatening penicillin allergies) 1

Adjunctive Measures

1. Elevation of the affected area to promote gravity drainage of edema and inflammatory substances 1

2. Treatment of predisposing factors:

   • Tinea pedis
   • Venous eczema/stasis dermatitis
   • Trauma
   • Edema
   • Obesity
   • Underlying cutaneous disorders 1

3. Consider systemic corticosteroids (prednisone 40 mg daily for 7 days) in non-diabetic adult patients with cellulitis 1

Hospitalization Criteria

Hospitalization is recommended if:

• Concern for deeper or necrotizing infection
• Poor adherence to therapy
• Infection in a severely immunocompromised patient
• Outpatient treatment is failing
• SIRS
• Altered mental status
• Hemodynamic instability 1

Prevention of Recurrent Cellulitis

For patients with 3-4 episodes of cellulitis per year despite treatment of predisposing factors, consider prophylactic antibiotics:

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

Special Considerations

• In lower-extremity cellulitis, carefully examine interdigital toe spaces as treating fissuring, scaling, or maceration may eradicate colonization with pathogens and reduce recurrence 1

• For recurrent cellulitis, addressing predisposing factors is crucial, including:

  • Lymphedema
  • Venous insufficiency
  • Obesity
  • Toe web abnormalities 1

• Treatment failure should prompt consideration of:

  • Resistant organisms
  • Secondary conditions mimicking cellulitis
  • Underlying complicating conditions (immunosuppression, chronic liver disease, chronic kidney disease) 3