For a stable patient with an arm abscess after incision and drainage, is a single intravenous vancomycin dose followed by a short course of oral anti‑MRSA antibiotics appropriate?

Management of Arm Abscess After I&D with Single Vancomycin Dose

Direct Answer

For a stable patient with an arm abscess after adequate incision and drainage, a single dose of vancomycin followed by oral anti-MRSA antibiotics is appropriate, with a recommended 5-10 day total course of oral therapy. 1

Treatment Algorithm

Primary Intervention

• Incision and drainage is the cornerstone of treatment and must be adequate before considering antibiotic therapy alone 1, 2, 3
• If source control is achieved through proper I&D, antibiotics serve as adjunctive therapy rather than primary treatment 3

Oral Antibiotic Selection After Single Vancomycin Dose

First-line oral options (in order of preference):

1. Trimethoprim-sulfamethoxazole (TMP-SMX): 160-320/800-1600 mg PO twice daily 1

   • Most commonly used for outpatient MRSA skin infections
   • Verify local susceptibility patterns before use 2

2. Doxycycline: 100 mg PO twice daily 1

   • Reliable alternative with good MRSA coverage
   • Avoid in pregnancy and children <8 years 2

3. Minocycline: 200 mg loading dose, then 100 mg PO twice daily 1, 4

   • Often superior to doxycycline or TMP-SMX when these agents fail 4
   • More reliably effective for CA-MRSA than doxycycline 4

4. Clindamycin: 300-450 mg PO three times daily 2

   • Only use if local MRSA resistance rates to clindamycin are <10% 2
   • Canadian pooled resistance exceeds 40%, making this less reliable in many regions 5

Treatment Duration

• 5-10 days for uncomplicated abscess with adequate drainage 1, 2
• 7-14 days for complicated infection with systemic symptoms or inadequate initial drainage 1, 2

Critical Pitfalls to Avoid

Antibiotic Selection Errors

• Never use beta-lactams alone (penicillin, amoxicillin, cephalexin, cephalosporins, cloxacillin) as they have zero activity against MRSA and will result in treatment failure 2, 3, 5
• Do not use rifampin as monotherapy or add it routinely to oral regimens for uncomplicated skin/soft tissue infections, as resistance develops rapidly without proven benefit 2, 3

Inadequate Source Control

• Failure to achieve adequate I&D leads to treatment failure regardless of antibiotic choice 3
• If the patient fails to improve on oral antibiotics despite proper drainage, consider inadequate source control first before changing antibiotics 3

When to Escalate Care

Admit for IV antibiotics if:

• Systemic toxicity persists despite oral antibiotics 2, 3
• Rapidly progressive infection despite treatment 2, 3
• Inability to achieve adequate surgical drainage 2, 3
• Signs of deeper extension (e.g., necrotizing fasciitis, septic thrombophlebitis) 1

For inpatient complicated SSTI requiring continued IV therapy:

• Vancomycin 30-60 mg/kg/day IV in 2-4 divided doses (15-20 mg/kg/dose every 8-12 hours) 1
• Alternative: Linezolid 600 mg IV/PO twice daily 1
• Duration: 7-14 days for complicated infections 1

Special Considerations for "Shooter's Abscess"

While the guidelines do not specifically address injection drug use-related abscesses differently, these patients warrant closer monitoring for:

• Deeper tissue involvement or vascular complications 1
• Concurrent bacteremia (consider blood cultures if systemically ill) 1
• Transition from IV to oral therapy should be done cautiously in complicated cases 1