Management of Incompletely Drained Chest Wall Abscess
The abscess requires repeat incision and drainage immediately to ensure complete evacuation of all purulent material, and antibiotics should be continued only if high-risk features are present after adequate re-drainage. 1
Immediate Surgical Intervention Required
Incomplete drainage is the most critical problem to address, as residual purulent material leads to treatment failure and recurrence rates up to 44%, particularly with loculated collections 1. The persistent firmness indicates inadequate source control, which is an absolute indication for repeat I&D 2, 1.
Technical approach to re-drainage:
- Extend the original incision or create additional incisions to break up loculations and ensure complete evacuation of all pus 1
- Probe the cavity gently to identify and break down any septations or pockets 1
- Do NOT pack the wound after drainage - packing causes more pain without improving healing outcomes 1
- Simply cover with dry sterile gauze 1
Antibiotic Decision After Adequate Re-Drainage
After achieving complete drainage, reassess whether antibiotics are truly indicated. The decision hinges on specific high-risk criteria 2, 1:
Continue antibiotics ONLY if any of these features are present:
- Erythema extending >5 cm beyond the abscess margins 1
- Systemic signs: Temperature >38°C, heart rate >90 bpm, respiratory rate >24/min, or WBC >12,000 or <4,000 cells/µL 2
- Rapid progression or worsening despite current treatment 2
- Immunocompromised state (diabetes, HIV, malignancy, immunosuppressive medications) 2
- Multiple sites of infection 2
- Associated septic phlebitis 2
STOP antibiotics if:
- The abscess is now adequately drained AND erythema is confined to <5 cm from wound margins AND no systemic signs are present 1. For simple abscesses with complete drainage, antibiotics contribute to resistance without improving outcomes 2, 1, 3.
Appropriate Antibiotic Coverage (If Indicated)
If antibiotics are warranted based on the criteria above, ensure MRSA coverage - community-acquired MRSA is the predominant pathogen in purulent skin infections 2, 4, 3.
First-line oral options for MRSA coverage:
- Clindamycin 300-450 mg PO three times daily 2
- TMP-SMX 1-2 double-strength tablets PO twice daily 2
- Doxycycline 100 mg PO twice daily 2
Clindamycin provides dual coverage against both MRSA and β-hemolytic streptococci, making it preferred when streptococcal infection cannot be excluded 2. However, it carries higher risk of Clostridioides difficile infection compared to other agents 2, 5.
TMP-SMX and doxycycline have excellent MRSA activity but uncertain activity against streptococci 2. If significant surrounding cellulitis suggests possible streptococcal involvement, clindamycin is the better choice 2.
Duration:
5-7 days is adequate for most cases when antibiotics are used 2, 5, but extend treatment if infection has not improved within this timeframe 2.
Critical Pitfalls to Avoid
- Never rely on antibiotics alone without ensuring complete drainage - antibiotics are adjunctive only and cannot compensate for inadequate source control 1, 5
- Do not use rifampin as monotherapy or adjunctive therapy - it offers no benefit and promotes resistance 2, 1
- Do not pack the wound - evidence shows no benefit and increased pain 1
- Do not prescribe ceftriaxone or other cephalosporins - they lack MRSA coverage, which is essential for purulent skin infections 1
Follow-Up Assessment
Reassess at 48-72 hours for decreased pain, swelling, and resolution of erythema 5. If no improvement occurs despite adequate re-drainage and appropriate antibiotics, consider: