What is the diagnosis and management of skin popping in Intravenous Drug Users (IVDU)?

Management of Skin Popping in Intravenous Drug Users

Skin popping in intravenous drug users (IVDU) requires prompt surgical drainage of abscesses combined with appropriate antibiotic therapy, with special attention to MRSA coverage. 1

Definition and Pathophysiology

Skin popping refers to subcutaneous injection of drugs when veins become less accessible. This practice often leads to:

• Abscess formation
• Cellulitis
• Tissue necrosis
• Polymicrobial infections

The injection of drugs and nonsterile substances causes local tissue damage, creating an environment favorable for bacterial infection 1. Main risk factors include:

• Use of unsterilized needles
• Injection of drug mixtures (e.g., "speedball")
• Poor injection technique
• Contaminated drug solutions

Clinical Presentation

Common findings:

• Erythematous, painful, fluctuant masses
• Cellulitis surrounding injection sites
• Hyperpigmented, fibrotic, depressed scars from previous infections 2
• Fever (present in 40-50% of cases) 1
• Systemic symptoms in severe cases

Locations:

• Commonly affects extremities, particularly lower extremities
• Areas where veins are less accessible or have been exhausted

Diagnosis

1. Physical examination:

   • Look for fluctuant masses, erythema, warmth
   • Assess for signs of systemic infection
   • Examine for hyperpigmented scars from previous skin popping 2

2. Laboratory studies:

   • Complete blood count with differential
   • Blood cultures if systemic symptoms present

3. Imaging:

   • Ultrasonography to distinguish cellulitis from abscess 1
   • CT with IV contrast for deeper or complex infections 3

4. Microbiological studies:

   • Culture and sensitivity testing of abscess material
   • Most common pathogens:
     • Staphylococcus aureus (frequently MRSA) 1
     • Polymicrobial infections including anaerobes 1
     • Streptococci species

Management

Surgical Management:

• Surgical drainage is the primary treatment for abscesses 3
• Incision and drainage with exploration for loculations
• Debridement of necrotic tissue
• Consider leaving wound open with packing for secondary intention healing
• Multiple counter incisions may be needed for large abscesses 1

Antibiotic Therapy:

• Empiric antibiotic regimen should cover MRSA and anaerobes 1

• First-line options:

  • Clindamycin 300-450 mg PO TID 3
  • Trimethoprim-sulfamethoxazole 1-2 DS tablets BID (for MRSA) 3
  • Doxycycline 100 mg PO BID (alternative for MRSA) 3

• For severe infections:

  • Vancomycin IV plus piperacillin-tazobactam or a carbapenem 1
  • Duration: 5-10 days for uncomplicated cases after drainage 3
  • Complex infections may require 6-8 weeks of IV antibiotics 3

Special Considerations:

• Screen for bloodborne infections (HIV, HBV, HCV) 1
• Evaluate for endocarditis if persistent signs of systemic infection 1
• Rule out foreign bodies (broken needles) with radiography 1
• Check for vascular complications with duplex sonography 1

Follow-up and Prevention

• Reassess 2-3 days after initial treatment 3

• If no improvement within 7 days, consider:

  • Diagnostic re-evaluation
  • Culture and sensitivity testing
  • Alternative antibiotic regimen 3

• Prevention strategies:

  • Addiction treatment referral is essential for long-term success 4
  • Surgical outcomes are directly related to addiction control 4
  • Education on harm reduction practices
  • Substance abuse counseling 1

Complications

• Mycotic aneurysms (especially in femoral, humeral, or axillary arteries) 1
• Necrotizing fasciitis
• Sepsis
• Endocarditis
• Chronic scarring and disfigurement 2
• Amputation (reported in 6% of cases) 5

Prognosis

Prognosis depends on:

• Severity of infection
• Timeliness of treatment
• Underlying comorbidities
• Continued substance use

Studies show that approximately 73% of patients do not return for scheduled follow-up visits, complicating long-term management 5.

Multidisciplinary Approach

A multidisciplinary team approach including surgery, infectious disease, addiction medicine, and social work is crucial for successful outcomes 4. Surgical treatment without addressing the underlying addiction has high failure rates.