What antibiotics are used to treat skin infections?

Antibiotic Treatment for Skin Infections

First-line treatment for skin infections is cephalexin 500 mg orally 4 times daily for 5-7 days or dicloxacillin 500 mg orally 4 times daily for 5-7 days. 1

Treatment Algorithm Based on Infection Type

Mild to Moderate Uncomplicated Skin Infections

• First-line options:

  • Cephalexin 500 mg orally 4 times daily for 5-7 days 1, 2
  • Dicloxacillin 500 mg orally 4 times daily for 5-7 days 1

• If MRSA is suspected or prevalent in community:

  • TMP-SMX 1-2 DS tablets (160/800 mg) twice daily for 5-7 days 1
  • Doxycycline 100 mg orally twice daily for 5-7 days 1
  • Clindamycin 300-450 mg orally 3 times daily for 5-7 days 1

Alternative Options for Mild Infections

• Amoxicillin-clavulanate 875/125 mg twice daily orally for 5-6 days 1

Severe Infections Requiring Inpatient Management

• Vancomycin 15 mg/kg IV every 12 hours 1
• Linezolid 600 mg IV/PO every 12 hours 1
• Consider adding gram-negative coverage if risk factors present 1

Pathogen-Specific Treatment

MRSA Infections

• Vancomycin 15-20 mg/kg IV every 8-12 hours 1
• Alternative: Daptomycin 6 mg/kg IV every 24 hours (for vancomycin-resistant or intolerant patients) 1

MSSA Infections

• Dicloxacillin or cephalexin 1
• Alternatives: Clindamycin or TMP-SMX 1

Group A Streptococcus Infections

• Penicillin 1
• Alternatives: Cephalexin or clindamycin 1

Treatment Duration

• Mild infections: 5-7 days 1
• Moderate infections: 7-10 days 1
• Severe infections: 10-14 days 1
• Immunocompromised patients: May require extended treatment based on clinical response 1

Special Populations and Considerations

Pediatric Patients

• Usual recommended dosage: 25-50 mg/kg/day in divided doses 2
• For skin infections: Total daily dose may be divided and administered every 12 hours 2
• Avoid doxycycline in children under 8 years due to risk of dental staining 1

Pregnant Patients

• Avoid doxycycline and use alternative antibiotics 1

Immunocompromised Patients

• May require broader coverage (e.g., vancomycin plus piperacillin-tazobactam or a carbapenem) 1

Clinical Pearls and Pitfalls

• Clinical improvement should be evident within 48-72 hours. If no improvement after 72 hours, reassess diagnosis and consider changing antibiotic regimen 1

• Obtain bacterial cultures from the affected area to guide targeted antibiotic therapy, especially in severe or recurrent infections 1

• Consider local resistance patterns when selecting antibiotics, including prevalence of MRSA and ESBL-producing organisms 1

• Cephalexin is not effective against MRSA - use appropriate alternatives like TMP-SMX, doxycycline, or clindamycin if MRSA is suspected 1

• Address predisposing factors to prevent recurrence:

  • Treat underlying skin conditions
  • Manage edema and venous insufficiency
  • Improve hygiene practices
  • Consider decolonization for recurrent MRSA infections 1

• Drainage is essential for abscesses and purulent collections - antibiotics alone may be insufficient without adequate drainage 3