What is the treatment for an open abscess on the back?

Treatment of Open Abscess on the Back

The primary treatment for an open abscess on the back is incision and drainage (I&D), with antibiotics reserved only for patients with systemic signs of infection, extensive surrounding cellulitis (>5 cm), or immunocompromising conditions. 1

Primary Treatment: Incision and Drainage

• I&D is the definitive treatment for cutaneous abscesses and should be performed promptly to evacuate infected material 1
• The incision should be adequate to ensure complete drainage of all purulent material and break up any loculations within the abscess cavity 1
• After drainage, the wound should heal by secondary intention with regular dressing changes 1, 2
• Simply covering the surgical site with a dry sterile dressing is usually the most effective wound management - packing causes more pain without improving healing outcomes 1

When Antibiotics Are NOT Needed

Most superficial abscesses can be managed with I&D alone without antibiotics if the patient meets ALL of the following criteria: 1, 2

• Temperature <38.5°C
• Heart rate <110 beats/minute
• White blood cell count <12,000 cells/µL
• Erythema/induration extending <5 cm from the wound edge
• No immunocompromising conditions (diabetes, immunosuppression, etc.)
• No signs of systemic inflammatory response syndrome (SIRS)

Studies of subcutaneous abscesses found little or no benefit for antibiotics when combined with adequate drainage 1

When Antibiotics ARE Indicated

Add antibiotic therapy if ANY of the following are present: 1, 2

• Temperature >38.5°C or heart rate >110 beats/minute
• Erythema extending >5 cm beyond wound margins
• SIRS criteria present (fever, tachycardia, tachypnea, abnormal WBC)
• Immunocompromised state
• Diabetes mellitus
• Failed drainage alone
• Signs of deeper tissue involvement

Antibiotic Selection for Back Abscesses

For trunk/back abscesses (clean areas away from axilla/perineum): 2

• First-line options: Cephalexin 500 mg PO every 6 hours 2, 3, OR dicloxacillin 250-500 mg PO every 6 hours 2, 3
• If MRSA suspected or confirmed: Add vancomycin 15 mg/kg IV every 12 hours 2, OR use clindamycin 300-450 mg PO every 6 hours 2, 4
• Duration: Typically 24-48 hours after adequate drainage if systemic signs resolve 1, 2

The back is typically colonized by Staphylococcus aureus and streptococci, making anti-staphylococcal coverage appropriate 1

Culture Recommendations

• Obtain Gram stain and culture of purulent material from the abscess to guide antibiotic therapy, though treatment without cultures is reasonable in typical cases 1
• This is particularly important if MRSA is prevalent in your community or if the patient has risk factors for resistant organisms 1

Critical Pitfalls to Avoid

• Inadequate drainage is the most common cause of treatment failure - ensure complete evacuation of all purulent material and break up loculations 1
• Do not use needle aspiration - it has only 25% success rate overall and <10% success with MRSA infections 1
• Delayed drainage can lead to progression of infection including potential necrotizing soft tissue infection 2
• Prescribing antibiotics without adequate drainage is ineffective - drainage is the definitive treatment 1
• If the abscess does not resolve as expected after proper I&D, investigate for deeper infection, foreign body, or underlying conditions 2

Follow-Up Care

• Continue dressing changes until wound heals by secondary intention 1, 2
• Monitor for recurrence, which can occur in up to 15% of cases with proper drainage 1
• Ensure antibiotics are continued for at least 48 hours after the patient becomes afebrile and asymptomatic if they were indicated 3