What is the best course of action for a recurrent soft tissue infection of the external ear following a dirty piercing, which initially responded to cefalexin (cephalexin) but returned a week later?

Recurrent Ear Piercing Infection Management

For a recurrent soft tissue infection of the external ear following dirty piercing that initially responded to cefalexin but returned, you should obtain wound culture, perform incision and drainage if an abscess has formed, and switch to an antibiotic with MRSA coverage such as trimethoprim-sulfamethoxazole, doxycycline, or clindamycin for 5-10 days, while implementing decolonization measures.

Immediate Assessment and Culture

• Obtain wound culture before starting new antibiotics to identify the causative pathogen and guide targeted therapy 1.
• The recurrence after initial cefalexin response strongly suggests either MRSA (which is resistant to cefalexin) or inadequate source control 1.
• Examine carefully for abscess formation, as piercing-related infections commonly develop purulent collections that require drainage 1.

Source Control

• Perform incision and drainage if any abscess or purulent collection is present - this is the primary treatment and antibiotics are adjunctive 1.
• Consider removing the piercing jewelry if still in place, as foreign material can perpetuate infection 1.
• The presence of foreign material (piercing) is a local factor that may cause recurrent abscess formation 1.

Antibiotic Selection

Switch from cefalexin to MRSA-active therapy:

• First-line options for MRSA coverage 1:

  • Trimethoprim-sulfamethoxazole 1-2 double-strength tablets twice daily
  • Doxycycline 100 mg twice daily
  • Clindamycin 300-450 mg four times daily

• The initial response to cefalexin followed by recurrence is a classic pattern for MRSA infection, where initial improvement occurs due to drainage/immune response, but the organism persists 2.

• Cefalexin lacks activity against MRSA, which has become the predominant pathogen in community-acquired skin infections, with prevalence rates exceeding 87% in some studies 2.

Treatment Duration

• Treat for 5-10 days with the MRSA-active antibiotic after obtaining cultures 1.
• Duration should be extended if infection has not improved within 5 days 1.

Decolonization Protocol

Implement a 5-day decolonization regimen to prevent further recurrences 1:

• Intranasal mupirocin twice daily for 5 days
• Daily chlorhexidine body washes
• Daily decontamination of personal items (towels, sheets, pillowcases, clothes)

This decolonization approach is specifically recommended for recurrent S. aureus infections, though evidence quality is limited 1.

Key Clinical Pitfalls

• Do not continue cefalexin - the recurrence indicates treatment failure, likely due to MRSA 1, 2.
• Do not rely on antibiotics alone if an abscess is present - surgical drainage is essential and antibiotics without drainage have poor outcomes 1.
• Do not assume the infection will resolve with the same antibiotic - recurrence at the same site requires culture-directed therapy and investigation for local factors 1.
• Piercing-related infections in the ear cartilage can progress to perichondritis, which may require more aggressive management if not adequately treated 1.

Follow-up

• Reassess within 24-48 hours to ensure clinical improvement 1.
• If no improvement or worsening occurs, consider hospitalization for intravenous antibiotics (vancomycin 15-20 mg/kg every 8-12 hours) 1.
• Adjust antibiotics based on culture results when available 1.