What is the next step in managing a patient with cellulitis?

Management of Cellulitis

The next step in managing a patient with cellulitis is to initiate oral antibiotic therapy with cephalexin 500 mg 3-4 times daily for 5-6 days as the first-line treatment. 1

Initial Antibiotic Selection

For uncomplicated cellulitis, empiric therapy should target the most common causative organisms:

• First-line options (for non-purulent cellulitis):

  • Cephalexin 500 mg 3-4 times daily for 5-6 days 1
  • Dicloxacillin 500 mg 4 times per day for 5-6 days 1

• For penicillin-allergic patients:

  • Clindamycin 300-450 mg three times daily for 5-6 days 1
  • Doxycycline 100 mg twice daily for 5-6 days (not for children under 8 years) 1

MRSA Considerations

Add MRSA coverage if risk factors are present:

• Previous MRSA infection
• Purulent drainage
• Systemic inflammatory response syndrome
• Penetrating trauma 1

MRSA coverage options include:

• Trimethoprim-sulfamethoxazole 1-2 double-strength tablets twice daily
• Doxycycline 100 mg twice daily
• Linezolid 600 mg twice daily 1

Severe Infections Requiring Hospitalization

For patients with severe infection requiring IV therapy:

• Nafcillin or oxacillin 1-2 g every 4 hours (for MSSA) 1
• Cefazolin 1 g every 8 hours (for penicillin-allergic patients without immediate hypersensitivity) 1
• Vancomycin 15-20 mg/kg IV every 8-12 hours (for MRSA or severe penicillin allergy) 1

Treatment Duration and Follow-up

• Standard duration is 5-6 days 1
• Reassess within 48-72 hours to evaluate clinical improvement 1
• Extend treatment if infection has not improved 1

Special Considerations and Pitfalls

Common Pitfalls to Avoid:

1. Failure to drain purulent collections - antibiotics alone are often insufficient for abscesses 1
2. Inadequate treatment duration - extend therapy if clinical response is inadequate 1
3. Overuse of broad-spectrum antibiotics - reserve vancomycin and newer agents for severe infections or confirmed MRSA 1
4. Failure to address predisposing factors - identify and treat conditions such as edema, obesity, eczema, venous insufficiency, and toe web abnormalities 1

Important Warnings

• Before initiating cephalexin, carefully inquire about previous hypersensitivity reactions to cephalosporins, penicillins, or other drugs 2
• Cross-hypersensitivity among beta-lactam antibiotics may occur in up to 10% of patients with penicillin allergy 2
• Monitor for Clostridium difficile-associated diarrhea, which can range from mild diarrhea to fatal colitis 2

Prevention of Recurrence

For patients with recurrent cellulitis (3-4 episodes per year), especially those with lymphedema:

• Consider antibiotic prophylaxis
• Benzathine penicillin given every 2-4 weeks is an effective long-term prophylactic option 1
• Treating underlying conditions is essential for preventing recurrence 1

Remember that cellulitis is primarily a clinical diagnosis based on the presence of erythema, warmth, swelling, and tenderness over the affected area 3. If the patient fails to improve with appropriate first-line antibiotics, consider resistant organisms or conditions that mimic cellulitis 3.