What is the recommended antibiotic regimen for vulvar cellulitis?

Treatment of Vulvar Cellulitis

For vulvar cellulitis, the recommended antibiotic regimen is an agent active against streptococci, with consideration for MRSA coverage depending on risk factors, typically for 5 days. 1

First-line Treatment Options

Mild Vulvar Cellulitis (without systemic signs):

• Oral options targeting streptococci:
  • Penicillin VK 250-500 mg every 6 hours
  • Cephalexin 500 mg every 6 hours
  • Clindamycin 300-450 mg every 8 hours (if penicillin allergic)
  • Erythromycin 400 mg four times daily (alternative for penicillin allergy)

Moderate Vulvar Cellulitis (with systemic signs):

• Oral options with MSSA coverage:
  • Dicloxacillin 500 mg four times daily
  • Cephalexin 500 mg four times daily
  • Clindamycin 300-450 mg every 8 hours

Severe Vulvar Cellulitis (with SIRS or risk factors for MRSA):

• Parenteral options:
  • Vancomycin 15 mg/kg every 12 hours IV (MRSA coverage)
  • Clindamycin 600-900 mg every 8 hours IV
  • Linezolid 600 mg every 12 hours (oral or IV)

Risk Factors for MRSA Coverage

Add MRSA coverage if any of the following are present 1:

• Previous MRSA infection
• MRSA nasal colonization
• Injection drug use
• Penetrating trauma
• Purulent drainage
• Systemic inflammatory response syndrome (SIRS)

Duration of Therapy

The recommended duration of antimicrobial therapy is 5 days, but treatment should be extended if the infection has not improved within this time period 1.

Special Considerations

For Vulvar Abscesses

• Incision and drainage is the primary treatment for abscesses 1, 2
• MRSA is a common cause of vulvar abscesses (64% in one study) 2
• Consider trimethoprim-sulfamethoxazole for empiric coverage of MRSA in vulvar abscesses 2

For Severe or Complex Infections

• For severely compromised patients or complex infections, consider broader coverage 1:
  • Vancomycin plus piperacillin-tazobactam
  • Vancomycin plus imipenem/meropenem

Adjunctive Measures

1. Elevation of the affected area to promote drainage of edema 1
2. Treatment of predisposing factors such as:
   • Edema
   • Underlying cutaneous disorders
   • Interdigital maceration
   • Fissuring or scaling 1
3. Consider systemic corticosteroids (prednisone 40 mg daily for 7 days) in non-diabetic patients to hasten resolution 1

Hospitalization Criteria

Consider hospitalization if 1:

• Concern for deeper or necrotizing infection
• Poor adherence to therapy
• Severely immunocompromised patient
• Outpatient treatment is failing
• SIRS, altered mental status, or hemodynamic instability

Prevention of Recurrence

For patients with recurrent episodes 1:

1. Identify and treat predisposing conditions
2. Consider prophylactic antibiotics for patients with 3-4 episodes per year:
   • Oral penicillin or erythromycin twice daily for 4-52 weeks
   • Intramuscular benzathine penicillin every 2-4 weeks

Remember that vulvar cellulitis is most commonly caused by streptococci, with S. aureus less frequently involved unless there is previous penetrating trauma or an underlying abscess 1.