What is the recommended treatment for leg cellulitis?

Treatment of Leg Cellulitis

The first-line treatment for typical leg cellulitis is a 5-day course of antibiotics active against beta-hemolytic streptococci, such as penicillin, amoxicillin, dicloxacillin, or cephalexin, with extension if no improvement is seen. 1

Antibiotic Selection Based on Clinical Presentation

Mild to Moderate Non-Purulent Cellulitis

• Beta-lactam monotherapy targeting streptococci is recommended as first-line treatment, as MRSA is an unusual cause of typical cellulitis 2, 1
• Options include:
  • Cephalexin 500mg four times daily 3
  • Dicloxacillin 500mg four times daily 1
  • Amoxicillin 500mg three times daily 1
  • Penicillin V 500mg four times daily 1
• For penicillin-allergic patients, alternatives include:
  • Clindamycin 300-450mg three times daily 1, 3
  • Erythromycin 500mg four times daily 2

Severe or High-Risk Cellulitis

• For patients with systemic symptoms, immunocompromise, or failed outpatient therapy, consider:
  • Vancomycin IV 2
  • Linezolid (oral or IV) 2
  • Daptomycin IV 2
• For severely compromised patients, broader coverage with vancomycin plus either piperacillin-tazobactam or a carbapenem is recommended 2

MRSA Coverage Considerations

• MRSA coverage should be added only in specific scenarios 2, 1:
  • Penetrating trauma
  • Evidence of MRSA infection elsewhere
  • Purulent drainage
  • Injection drug use
  • Prior MRSA exposure
  • Failed beta-lactam therapy

Treatment Duration

• 5 days of antibiotic therapy is sufficient for most cases 2, 1
• Extend treatment if infection has not improved within 5 days 2
• Clinical improvement should be evident within 48-72 hours of starting appropriate therapy 4

Adjunctive Measures

• Elevate the affected area to promote gravity drainage of edema and inflammatory substances 2, 1
• Identify and treat predisposing conditions 2:
  • Tinea pedis (carefully examine interdigital spaces) 2
  • Venous insufficiency 1
  • Lymphedema 1
  • Skin trauma or fissures 2
• Consider systemic corticosteroids (prednisone 40mg daily for 7 days) in non-diabetic adults to hasten resolution 2, 1

Hospitalization Criteria

• Hospitalize patients with 2:
  • 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

Prevention of Recurrence

• For patients with ≥3-4 episodes per year despite addressing predisposing factors, consider prophylactic antibiotics 2, 1:
  • Oral penicillin or erythromycin twice daily for 4-52 weeks 2
  • Intramuscular benzathine penicillin every 2-4 weeks 2
• Prophylactic antibiotics reduce recurrence risk by 69% while on treatment 5
• Preventive effects diminish after discontinuation of prophylaxis 5

Common Pitfalls to Avoid

• Unnecessary MRSA coverage for typical non-purulent cellulitis 3
• Failure to examine interdigital toe spaces for fissuring or maceration 2
• Not elevating the affected area 2, 3
• Inadequate treatment of predisposing conditions 1
• Insufficient duration of therapy when clinical improvement is delayed 2