What antibiotic is recommended for an infected ingrown toenail?

Antibiotic Treatment for Infected Ingrown Toenails

For infected ingrown toenails, oral trimethoprim-sulfamethoxazole or amoxicillin-clavulanate are recommended as first-line antibiotics for mild to moderate infections, while clindamycin is appropriate for patients with penicillin allergies. 1

Classification of Infection Severity

• Mild infection: Local inflammation, pain, and minimal discharge; can often be treated with topical measures and oral antibiotics if needed 1
• Moderate infection: More extensive inflammation, purulent discharge, and pain limiting instrumental activities of daily living 1
• Severe infection: Significant inflammation extending beyond the toe, systemic symptoms, or limiting self-care activities 1

Antibiotic Selection Based on Severity

Mild Infections

• First-line oral options:
  • Dicloxacillin
  • Cephalexin
  • Clindamycin (for penicillin-allergic patients)
  • Trimethoprim-sulfamethoxazole
  • Amoxicillin-clavulanate 1

Moderate Infections

• Oral options:
  • Trimethoprim-sulfamethoxazole
  • Amoxicillin-clavulanate
  • Levofloxacin
  • Clindamycin 1

Severe Infections

• Require initial intravenous therapy:
  • Piperacillin-tazobactam
  • Levofloxacin or ciprofloxacin with clindamycin
  • Vancomycin (if MRSA is suspected) 1

Important Considerations

• Antibiotics should be used for a defined period based on infection severity:

  • Mild infections: 1-2 weeks usually sufficient
  • Moderate infections: 2-4 weeks depending on response 1

• Topical antimicrobial measures should be used concurrently:

  • Povidone-iodine 2% soaks
  • Topical antibiotics with corticosteroids for inflammation 1

• Evidence suggests that in healthy patients without extensive cellulitis, a chemical matrixectomy procedure alone without antibiotics may be equally effective as using antibiotics 2

• Staphylococcus aureus is the most common pathogen in infected ingrown toenails, but polymicrobial infections including gram-negative organisms can occur 1, 3

Management Algorithm

1. Assess infection severity (mild, moderate, severe) 1

2. For mild-moderate infections:

   • Begin appropriate oral antibiotic (see above)
   • Implement concurrent local measures:
     • Warm water soaks with Epsom salts 4
     • Cotton wisps or dental floss under the ingrown nail edge 5, 6
     • Correcting improper footwear 5

3. For severe infections:

   • Begin intravenous antibiotics
   • Consider surgical consultation for drainage 1

4. Monitor response within 2-5 days for outpatients 1

   • If no improvement, consider:
     • Changing antibiotic based on culture results
     • Surgical intervention

Surgical Considerations

• Partial nail avulsion is the most common surgical approach for moderate-severe cases 5, 6
• Antibiotics may not improve outcomes when appropriate surgical intervention is performed 2
• Systemic antibiotics are ineffective for paronychia unless infection is proven 3

Common Pitfalls to Avoid

• Don't use systemic antibiotics without evidence of infection 3
• Don't continue antibiotics for the entire time the wound remains open; use for a defined period based on clinical response 1
• Don't overlook contributing factors such as hyperhidrosis, improper nail trimming, or inadequate footwear 5
• Don't miss secondary fungal infections which may require antifungal treatment 1