How should an otherwise healthy adult with a skin wound infection on the chest be managed?

Management of Skin Wound Infection on the Chest

For an otherwise healthy adult with a skin wound infection on the chest, first determine if the infection is purulent or nonpurulent, then assess severity based on systemic signs—mild purulent infections require incision and drainage (I&D) with consideration for adjunctive antibiotics, while nonpurulent cellulitis requires oral antibiotics active against streptococci and staphylococci. 1

Initial Assessment and Classification

The IDSA guidelines provide a clear framework for categorizing skin and soft tissue infections (SSTIs) that directly determines management 1:

Purulent vs. Nonpurulent Infection

Purulent infections (abscesses, carbuncles, furuncles):

• Look for fluctuance, purulent drainage, or localized collection
• These are primarily caused by S. aureus
• I&D is the primary treatment (strong recommendation, high-quality evidence) 1

Nonpurulent infections (cellulitis, erysipelas):

• Erythema, warmth, swelling without purulent focus
• Primarily caused by β-hemolytic streptococci, though S. aureus can be involved
• Antibiotics are the primary treatment

Severity Stratification

Mild infection:

• No systemic signs
• Temperature <38°C
• Heart rate <90 bpm
• Respiratory rate <24 breaths/min
• Normal WBC count

Moderate infection:

• Systemic signs present (fever ≥38°C, tachycardia, tachypnea, or abnormal WBC)
• Patient otherwise stable

Severe infection:

• Failed oral antibiotic treatment
• Signs of deeper infection (bullae, skin sloughing)
• Hypotension or organ dysfunction
• Immunocompromised status

Treatment Algorithm

For Purulent Infections (Abscess/Furuncle)

1. Incision and drainage is mandatory 1

   • This alone may be sufficient for small, uncomplicated abscesses in healthy patients

2. Add antibiotics if:

   • Systemic signs of infection present
   • Erythema >5 cm from the wound
   • Multiple sites of infection
   • Rapid progression despite I&D
   • Immunocompromised

3. Antibiotic selection for purulent SSTIs:

   • First-line oral agents (covering MRSA):
     • Trimethoprim-sulfamethoxazole (TMP-SMX)
     • Doxycycline
     • Clindamycin
   • Duration: 5-10 days depending on response
   • If MRSA unlikely (community-specific): cephalexin or dicloxacillin

4. Culture recommendations:

   • Gram stain and culture of pus are recommended but treatment without these is reasonable in typical cases 1

For Nonpurulent Infections (Cellulitis)

Mild cellulitis:

• Oral antibiotics for 5-7 days:
  • Cephalexin 500 mg four times daily
  • Dicloxacillin 500 mg four times daily
  • These cover streptococci and MSSA

If MRSA suspected (based on local epidemiology, purulent drainage, or prior MRSA):

• Add MRSA coverage: TMP-SMX, doxycycline, or clindamycin
• Common pitfall: Overuse of MRSA-active agents when streptococcal cellulitis is more likely—true nonpurulent cellulitis is rarely caused by MRSA

Moderate cellulitis with systemic signs:

• Consider IV antibiotics initially:
  • Cefazolin 1-2 g IV every 8 hours
  • Vancomycin if MRSA suspected or β-lactam allergy
• Transition to oral when improving (typically 24-48 hours)

For Surgical/Traumatic Wounds

The IDSA algorithm for surgical site infections provides specific guidance 1:

If fever develops within 48 hours post-injury:

• Unlikely to be wound infection
• Seek other fever sources

If erythema/induration present:

• Erythema ≤5 cm, temp <38°C, no systemic illness: Observe with dressing changes, no antibiotics
• Erythema >5 cm or temp ≥38°C: Begin antibiotics
  • Start cefazolin OR vancomycin (if high MRSA prevalence or β-lactam allergy)
  • If wound involves perineum or GI tract: add anaerobic coverage with metronidazole or use carbapenem

If purulent drainage present:

• Open and debride
• Obtain Gram stain to rule out streptococci and clostridia
• If either found: add penicillin and clindamycin immediately

Critical Considerations

Necrotizing Soft Tissue Infections

Red flags requiring immediate surgical consultation 2, 3:

• Pain out of proportion to exam findings
• Skin sloughing, bullae, or crepitus
• Rapid progression over hours
• Systemic toxicity
• Early debridement is essential to reduce mortality—delays worsen outcomes significantly

Wound Care Adjuncts

Beyond antibiotics 4, 5:

• Debridement of necrotic tissue reduces bioburden
• Appropriate moisture-retentive dressings
• Vacuum-assisted closure for complex wounds after debridement 2
• Avoid cytotoxic agents (hydrogen peroxide, povidone-iodine for prolonged use) that impair healing

Common Pitfalls

1. Over-reliance on swabs: Superficial swabs often grow contaminants and colonizers rather than true pathogens 6. For chronic or complex wounds, deep tissue biopsy or aspirate provides better microbiological accuracy, though this doesn't always change clinical outcomes.

2. Unnecessary antibiotics for simple abscesses: I&D alone is often sufficient for uncomplicated purulent infections in healthy patients 1

3. Inadequate drainage: Antibiotics cannot penetrate abscesses effectively—surgical drainage is non-negotiable

4. Missing necrotizing infections: Any suspicion warrants immediate surgical evaluation—don't wait for imaging or laboratory confirmation

5. Antibiotic duration: Shorter courses (5-7 days) are often adequate if source control achieved and clinical improvement evident