What is the best treatment for a skin infection?

Treatment of Skin Infections

For skin infections, amoxicillin-clavulanate (875/125 mg twice daily for 7 days) is the recommended first-line treatment due to its broad coverage against common causative organisms including Staphylococcus aureus and Streptococcus species. 1, 2

Classification and Treatment Algorithm

1. Uncomplicated Skin Infections

• Impetigo/Localized infections:
  • First choice: Topical mupirocin 2% ointment applied 2-3 times daily for 5-7 days 2
  • Alternative topical: Retapamulin or fusidic acid 2
  • If oral therapy needed: Cephalexin 500 mg four times daily for 7-10 days 3, 4

2. Moderate Skin and Soft Tissue Infections

• Cellulitis/Erysipelas:
  • First choice: Amoxicillin-clavulanate 875/125 mg twice daily for 7 days 1, 2
  • For penicillin allergy: Clindamycin 300-450 mg every 6-8 hours for 7-10 days 5
  • MRSA suspected: Trimethoprim-sulfamethoxazole (160-800 mg) twice daily or doxycycline 100 mg twice daily 1, 2

3. Severe/Complicated Skin Infections

• Necrotizing infections/Severe cellulitis:
  • First choice: Piperacillin-tazobactam plus vancomycin IV 1
  • Alternative: Carbapenem (imipenem, meropenem, ertapenem) 1
  • For mixed infections: Ampicillin-sulbactam 1.5-3g IV every 6-8 hours plus clindamycin 600-900 mg IV every 8 hours 1

4. Animal/Human Bite Infections

• First choice: Amoxicillin-clavulanate 875/125 mg twice daily 1
• Alternative: Doxycycline 100 mg twice daily (excellent for Pasteurella multocida) 1

Special Considerations

For Children

• Adjust dosing by weight:
  • Cephalexin: 25-50 mg/kg/day divided in 4 doses 3
  • For otitis media: 75-100 mg/kg/day in 4 divided doses 3
  • Clindamycin: 8-16 mg/kg/day divided in 3-4 doses for serious infections 5
• Avoid doxycycline in children under 8 years 2

For Immunocompromised Patients

• Use broader spectrum coverage initially
• Consider early IV therapy with piperacillin-tazobactam or a carbapenem 1
• Obtain cultures before starting antibiotics when possible 2

Duration of Treatment

• Standard duration: 7-10 days 2, 6
• For streptococcal infections: minimum 10 days to prevent complications 3, 5
• For necrotizing infections: continue until clinical improvement, often 2-3 weeks 1

Common Pitfalls to Avoid

1. Failing to consider MRSA in recalcitrant infections - obtain cultures when infections don't respond to initial therapy 2
2. Using penicillin alone for mixed infections - it's inferior to broader spectrum options 4
3. Inadequate duration of therapy - particularly for streptococcal infections which require at least 10 days 5
4. Relying solely on topical therapy for extensive disease 2, 6
5. Not addressing underlying conditions that may predispose to recurrent infection 2

When to Consider IV Therapy

• Extensive or rapidly spreading infection
• Systemic symptoms (fever, hypotension)
• Immunocompromised host
• Failed oral therapy
• Necrotizing infections 1

Tetanus Prophylaxis

• Administer tetanus toxoid to patients without vaccination within 10 years 1
• Tdap is preferred over Td if not previously given 1

By following this treatment algorithm and considering the patient-specific factors, most skin infections can be effectively managed with appropriate antibiotic therapy, resulting in reduced morbidity and improved outcomes.