What is the recommended management of cellulitis with Keflex (cephalexin)?

Management of Cellulitis with Keflex (Cephalexin)

For typical uncomplicated cellulitis, cephalexin 500 mg four times daily for 5 days is the recommended first-line treatment, with extension if the infection has not improved within this period. 1

Diagnosis and Assessment

Before initiating treatment, determine the severity of cellulitis:

• Mild cellulitis: No systemic signs of infection
• Moderate cellulitis: Systemic signs of infection without hemodynamic instability
• Severe cellulitis: Systemic signs with hemodynamic instability or altered mental status

Treatment Algorithm

Dosing and Duration

• Standard dose: 500 mg orally four times daily 1, 2
• High-dose option: 1000 mg orally four times daily may be considered for more severe cases (preliminary evidence suggests fewer treatment failures but more minor side effects) 3
• Duration: 5 days initially, extend if not improved 1

Patient Selection for Outpatient Management with Cephalexin

Cephalexin monotherapy is appropriate for:

• Typical uncomplicated cellulitis without purulent drainage 1
• Patients without SIRS, altered mental status, or hemodynamic instability 1
• Patients without evidence of MRSA infection elsewhere 1

When to Consider Alternative or Additional Coverage

Add coverage for MRSA (vancomycin, daptomycin, linezolid, TMP-SMX, or doxycycline) if:

• Cellulitis is associated with penetrating trauma 1
• Evidence of MRSA infection elsewhere 1
• Nasal colonization with MRSA 1
• History of injection drug use 1
• Presence of SIRS 1
• Purulent drainage is present 1

Important Adjunctive Measures

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

2. Identify and treat predisposing conditions 1:

   • Edema
   • Obesity
   • Eczema
   • Venous insufficiency
   • Toe web abnormalities (particularly important in lower-extremity cellulitis)

3. Consider systemic corticosteroids (prednisone 40 mg daily for 7 days) in nondiabetic adult patients to hasten resolution 1, 4

Monitoring and Follow-up

• Assess for clinical improvement within 48-72 hours
• If no improvement after 5 days of therapy, extend treatment course 1
• Consider hospitalization if:
  • Concern for deeper or necrotizing infection
  • Poor adherence to therapy
  • Severely immunocompromised patient
  • Outpatient treatment is failing 1

Prevention of Recurrence

For patients with recurrent cellulitis (3-4 episodes per year):

• Treat predisposing factors (especially toe web abnormalities)
• Consider prophylactic antibiotics:
  • Oral penicillin or erythromycin twice daily for 4-52 weeks
  • Intramuscular benzathine penicillin every 2-4 weeks 1

Common Pitfalls to Avoid

1. Overtreatment for MRSA: Evidence shows that MRSA is an unusual cause of typical cellulitis without purulence. Adding TMP-SMX to cephalexin does not improve outcomes in uncomplicated cellulitis 5, 6.

2. Inadequate duration: While 5 days is recommended initially, treatment should be extended if the infection has not improved within this time period 1.

3. Neglecting adjunctive measures: Elevation of the affected area and treatment of predisposing factors are crucial components of effective management 1.

4. Missing deeper infections: Always assess for signs of deeper infection requiring surgical consultation, especially if there's systemic toxicity 1.

5. Failure to examine interdigital spaces: In lower-extremity cellulitis, treating fissuring, scaling, or maceration between toes can prevent recurrence 1.