What is the recommended antibiotic for a patient with cellulitis on the lower extremity who is allergic to Keflex (Cephalexin)?

Antibiotic Recommendations for Cellulitis in Patients with Keflex Allergy

For patients with cellulitis on the lower extremity who have an allergy to Keflex (cephalexin), clindamycin is the recommended first-line antibiotic treatment. 1, 2

First-Line Options for Keflex-Allergic Patients

• Clindamycin 300-450 mg orally four times daily for 5 days is the preferred treatment for patients with a Keflex allergy 1, 2
• Clindamycin provides excellent coverage against streptococci, which are the most common causative pathogens in cellulitis of the lower extremities 1
• For patients unable to tolerate clindamycin, alternative options include:
  • Trimethoprim-sulfamethoxazole (if MRSA is suspected) 1, 2
  • Doxycycline (if MRSA is suspected) 1, 2

Treatment Duration and Monitoring

• A 5-day course of antibiotic therapy is as effective as a 10-day course for uncomplicated cellulitis if clinical improvement occurs within the first 5 days 1, 2
• Treatment should be extended if the infection has not improved within 5 days 1, 2
• Monitor for signs of clinical improvement including:
  • Reduction in erythema and swelling
  • Decreased pain and tenderness
  • Resolution of systemic symptoms if present 1

Special Considerations for MRSA Coverage

• Standard cellulitis is usually caused by streptococci, and MRSA is an unusual cause of typical cellulitis 1, 2
• Consider MRSA coverage only if the cellulitis is associated with:
  • Penetrating trauma 1, 2
  • Evidence of MRSA infection elsewhere 1, 2
  • Presence of purulent drainage 1, 2
  • History of injection drug use 1, 2
  • Presence of systemic inflammatory response syndrome (SIRS) 1, 2

Parenteral Options for Moderate to Severe Infections

• For patients requiring intravenous therapy due to severity of infection:
  • Vancomycin is recommended for patients with severe penicillin allergies 1
  • Daptomycin is an effective alternative for complicated skin infections, particularly when MRSA is suspected 3
  • Linezolid or telavancin are other options for patients with severe infections 1, 2

Adjunctive Measures

• Elevation of the affected area to promote gravity drainage of edema and inflammatory substances 1, 2
• Treatment of predisposing factors such as tinea pedis, venous insufficiency, or underlying cutaneous disorders 1, 2
• Careful examination of interdigital toe spaces to identify and treat fissuring, scaling, or maceration 1, 2
• Systemic corticosteroids (e.g., prednisone 40 mg daily for 7 days) could be considered in non-diabetic adult patients to hasten resolution 1, 2

Hospitalization Criteria

• Consider hospitalization if:
  • There is concern for deeper or necrotizing infection 1, 2
  • The patient has poor adherence to therapy 1, 2
  • The infection is in a severely immunocompromised patient 1, 2
  • Outpatient treatment is failing 1, 2
  • The patient has SIRS, altered mental status, or hemodynamic instability 1, 2

Prevention of Recurrence

• Identify and treat predisposing conditions such as edema, obesity, eczema, venous insufficiency, and toe web abnormalities 1, 2
• For patients with 3-4 episodes per year despite addressing predisposing factors, consider prophylactic antibiotics:
  • Oral penicillin or erythromycin twice daily for 4-52 weeks 1, 2, 4
  • Intramuscular benzathine penicillin every 2-4 weeks 1, 2, 4
  • Intramuscular clindamycin may be a reasonable alternative for penicillin-allergic patients with recurrent cellulitis 4