Human and Animal Bites

Bite wounds are polymicrobial inoculation injuries, not ordinary cellulitis. Human bites contain oral streptococci, Eikenella corrodens, and anaerobes; cat and dog bites frequently involve Pasteurella multocida and can involve Capnocytophaga canimorsus.^[1] Good wound management, tetanus/rabies assessment, and recognition of deep structural injury are as important as antibiotics. Amoxicillin/clavulanate is 1st-line oral therapy because it reliably covers the expected mixed flora — narrower agents (cephalexin, cloxacillin, clindamycin, or macrolide monotherapy) do not.

• Hand, face, foot, or genital location.
• Deep puncture or crush injury.
• Delayed presentation.
• Proximity to joint, tendon sheath, bone, or prosthetic joint.
• Diabetes, immunosuppression, advanced liver disease, or asplenia.
• Significant edema or vascular compromise.

• Identify species/person, time of injury, and provoked/unprovoked animal behaviour.
• Assess depth, contamination, tendon function, joint movement, neurovascular status, and any foreign body/tooth fragment.
• Assess tetanus immunization status and give indicated prophylaxis per the current Canadian Immunization Guide.^[2]
• Complete a rabies exposure assessment using current public-health guidance — antibiotics do not replace rabies post-exposure prophylaxis.^[3]
• Culture only clinically infected wounds; do not routinely culture fresh uninfected bites.

• Prevent or treat polymicrobial infection.
• Protect tendon, joint, bone, and neurovascular structures.
• Prevent tetanus and rabies when exposure warrants prophylaxis.
• Achieve wound healing without trapping infection.

• Copious irrigation is mandatory.
• Debride devitalized tissue and remove foreign material.
• Do not routinely close high-risk puncture wounds or infected wounds primarily.
• Elevate an injured hand/limb.
• Update tetanus immunization as indicated.
• Complete rabies risk assessment and public-health consultation when appropriate.

Pregnancy

Amoxicillin/clavulanate is preferred when susceptible/appropriate. Avoid doxycycline-based alternatives when another effective regimen is available.

Asplenia or severe immunocompromise

Use a lower threshold for prophylaxis, systemic therapy, and urgent assessment — Capnocytophaga infection can become severe rapidly in these patients.

Children

Use weight-based amoxicillin/clavulanate dosing. Any suspected joint/tendon/hand deep injury warrants medical assessment.

High-risk bite wounds require reassessment within 24-48 hours. Worsening pain, reduced joint range of motion, new swelling, fever, or lymphangitic spread requires urgent review. Treatment duration should be extended for deeper infections such as tenosynovitis, septic arthritis, or osteomyelitis under specialist direction.

1. Re-examine for retained foreign body, devitalized tissue, or closed-space infection.
2. Culture infected drainage.
3. Confirm the regimen covers Pasteurella/Capnocytophaga/Eikenella and anaerobes as appropriate.
4. Assess tendon, joint, and bone involvement.
5. Escalate to IV therapy and surgery/infectious-diseases consultation when deep infection or systemic illness is present.

• Using cephalexin alone for a cat or dog bite.
• Missing a closed-fist human bite because the skin wound is small.
• Forgetting tetanus and rabies assessment.
• Closing a contaminated puncture wound without considering infection risk.
• Treating a deep hand infection with oral antibiotics alone.

How to use this table: Doses are adult doses and require patient-specific confirmation (renal/hepatic function, weight, allergy history). Pediatric dosing is weight-based per the current product monograph unless stated. Drug pricing is intentionally omitted. Select any drug name to open its complete Pharmasist Drug Database page.

Oral therapy

Parenteral therapy