Should a separate course of antibiotics be prescribed one week after completing treatment for a human bite?

Repeating Antibiotic Therapy for Human Bites One Week Apart

No, you should not prescribe a separate course of antibiotics one week after completing treatment for a human bite unless there is clinical evidence of new or persistent infection. 1

Treatment Duration for Human Bite Infections

• The standard treatment duration for uncomplicated human bite infections is 7-10 days total. 1
• Once this course is completed and the infection has resolved clinically (no fever, decreasing erythema, reduced swelling, no purulent drainage), no additional antibiotics are indicated. 1
• Extending or repeating antibiotic courses without documented infection violates guideline recommendations and promotes antimicrobial resistance. 1

When Additional Antibiotics ARE Indicated

Additional antibiotic therapy beyond the initial 7-10 day course is only warranted if:

• Signs of persistent or recurrent infection develop (increasing pain, erythema, swelling, purulent drainage, fever). 1
• Deep structure involvement is present, requiring extended treatment:
  • Septic arthritis: 3-4 weeks total duration 1
  • Osteomyelitis: 4-6 weeks total duration 1
  • Tenosynovitis or deep hand infections: often require longer courses 2

Critical Timing Considerations for Human Bites

• Prophylactic antibiotics are only beneficial when given within 24 hours of the bite for high-risk wounds. 1
• If a patient presents ≥24 hours after the bite without signs of infection, prophylactic antibiotics should NOT be prescribed. 1
• Human bites have a 20-25% infection rate, with closed-fist injuries (CFI) over the metacarpophalangeal joints carrying the highest risk. 1, 3

High-Risk Features Requiring Initial Treatment

Prophylactic or therapeutic antibiotics are indicated for human bites with:

• Location: Hand, face, foot, genitals, or near joints 1
• Wound characteristics: Deep wounds, puncture wounds, wounds penetrating periosteum or joint capsule 1
• Patient factors: Immunocompromised status, diabetes, advanced liver disease, asplenia, prosthetic joints or heart valves 1
• Closed-fist injuries (striking someone's teeth with a clenched fist) warrant aggressive management due to high complication rates. 3, 4

First-Line Antibiotic Regimen

• Amoxicillin-clavulanate 875/125 mg twice daily is the preferred oral agent, providing coverage against the polymicrobial flora including Eikenella corrodens, Staphylococcus aureus, Streptococcus pyogenes, and anaerobes. 1, 2
• For penicillin allergy, alternatives include doxycycline or moxifloxacin as monotherapy. 1

Common Pitfalls to Avoid

• Do not prescribe antibiotics "just in case" at late presentation (>24 hours) without infection, as this violates guidelines and promotes resistance. 1
• Do not use first-generation cephalosporins, macrolides, or penicillinase-resistant penicillins alone, as they have poor activity against Eikenella corrodens (present in human bite wounds). 1, 3
• Closed-fist injuries require aggressive irrigation, debridement, and close follow-up due to their notorious high morbidity when treatment is delayed. 3, 4
• Mean delay in seeking care for severely infected human bites is 2.5 days versus 0.5 days for less severe infections, emphasizing the importance of early presentation. 4

Follow-Up Algorithm

• Patients should return immediately if signs of infection develop or worsen during or after treatment. 1
• Hand wounds require closer monitoring due to risk of septic arthritis, osteomyelitis, and tendon involvement. 1, 4
• If infection persists or worsens despite appropriate oral therapy, hospitalization for IV antibiotics and surgical consultation is indicated. 1, 4

Human bite infections that are established and deep carry a 27% complication rate (stiffness, recurrent infection, other infectious complications), confirming the high morbidity when treatment is delayed. 4