What antibiotics are recommended for a purulent infection on a finger that prevents biting?

Treatment of Purulent Finger Infection

For a purulent finger infection (felon or abscess), incision and drainage is the primary treatment, and antibiotics should be added if there is associated cellulitis, systemic signs, or inability to adequately drain the infection. 1

Initial Management Approach

• Incision and drainage is essential and often sufficient for simple abscesses without antibiotics 1
• Add antibiotics if the infection involves: 1
  • Surrounding cellulitis extending beyond the abscess
  • Systemic symptoms (fever, chills, malaise)
  • Involvement of difficult-to-drain areas (hand, fingers, face)
  • Rapid progression despite drainage
  • Immunocompromised status or significant comorbidities

Recommended Antibiotic Regimens

First-Line Oral Antibiotics (Outpatient)

For empiric coverage of purulent skin infections, the following oral options are recommended: 1

• Clindamycin 300-450 mg three times daily - provides coverage for both Staphylococcus aureus (including community-acquired MRSA) and Streptococcus species 1, 2
• Trimethoprim-sulfamethoxazole (TMP-SMX) 160-800 mg twice daily - excellent MRSA coverage but lacks streptococcal activity 1
• Doxycycline 100 mg twice daily - covers MRSA but not streptococci 1

When to Cover Both MRSA and Streptococci

If you need coverage for both organisms (recommended for hand infections with cellulitis): 1

• Clindamycin alone (covers both) 1
• TMP-SMX or doxycycline PLUS amoxicillin 500 mg three times daily (combination covers both) 1

Alternative First-Line Options for MSSA-Predominant Areas

If local MRSA rates are low (<10-15%) and no MRSA risk factors present: 1

• Cephalexin 500 mg four times daily 1, 3
• Dicloxacillin 500 mg four times daily 4, 5

These penicillinase-resistant agents are highly effective against methicillin-susceptible S. aureus (MSSA), which remains the most common pathogen in many settings 6, 7

Duration of Therapy

• 5-7 days of antibiotics is typically adequate for purulent skin infections that respond to drainage 1, 7
• Extend to 10 days if clinical improvement is slow or infection is extensive 1

Critical Pitfalls to Avoid

• Never use rifampin alone or as routine adjunctive therapy - resistance develops rapidly and it provides no benefit for simple skin infections 1
• Do not prescribe antibiotics without adequate drainage - antibiotics are largely ineffective for undrained purulent collections 1
• Ensure adequate fluid intake with dicloxacillin - take with at least 4 ounces of water and avoid taking immediately before bed to prevent esophageal irritation 5
• Consider MRSA risk factors including: prior MRSA infection, injection drug use, recent hospitalization, or local MRSA prevalence >10-15% 1

When to Escalate Care

Seek urgent surgical consultation if: 1

• Deep space infection suspected (tenosynovitis, deep palmar space infection)
• Systemic toxicity present (hypotension, altered mental status)
• Failure to improve within 48-72 hours of drainage and antibiotics 1
• Concern for necrotizing infection (severe pain out of proportion, rapid progression, skin necrosis) 1

Special Considerations for Hand Infections

Hand infections require particular attention because: 1

• Anatomic compartments can trap infection and lead to rapid progression
• Delayed treatment risks permanent functional impairment
• Foreign bodies (splinters, needles) must be ruled out radiographically 1
• Empiric MRSA coverage is prudent given the serious consequences of treatment failure 1