What are the clinical manifestations after a bite?

Clinical Manifestations After a Bite

After a bite wound, you should observe for signs of infection (which develops in 10-20% of cases overall), with cat bites having the highest infection rate at 30-50%, followed by human bites at 20-25%, and dog bites at 5-25%. 1

Immediate Local Wound Findings

Wound characteristics vary by bite type:

• Cat bites: Deep puncture wounds with minimal crush injury but higher risk of deep tissue penetration, osteomyelitis, and septic arthritis 1
• Dog bites: More extensive crush injury and tissue trauma with lacerations 1
• Human bites: Can be occlusive injuries (actual biting) or clenched-fist injuries (fist striking teeth), often more serious than animal bites 1

Signs of Infection to Monitor

Watch for these infectious complications, which typically manifest within 24-48 hours:

Early Signs (within 24-48 hours)

• Local cellulitis with erythema, warmth, and swelling around the wound 1
• Purulent drainage from the wound site 1
• Lymphangitis (red streaking) 2
• Regional lymphadenopathy 2
• Pain disproportionate to injury severity, especially near bones or joints, suggesting periosteal penetration 1

Serious Complications

• Septic arthritis - particularly with hand wounds and deep punctures 1
• Osteomyelitis - more common with cat bites due to deep penetration 1
• Tenosynovitis - inflammation of tendon sheaths 2
• Subcutaneous abscess formation 2
• Compartment syndrome - especially in hand injuries 1

Systemic Manifestations

• Fever, headache, and malaise may accompany wound infection 1
• Bacteremia and sepsis - rare but can occur, especially with Capnocytophaga canimorsus in asplenic or immunocompromised patients 1
• Endocarditis, meningitis, brain abscess - uncommon but serious complications 2

High-Risk Anatomic Locations

Certain bite locations carry higher infection risk and warrant closer observation: 1

• Hands - highest risk for serious complications including joint/bone involvement
• Feet - increased infection risk
• Face - cosmetic concerns and proximity to vital structures
• Genitals - high infection risk
• Areas near joints - risk of septic arthritis
• Wounds over prosthetic devices or implants (e.g., artificial heart valves) 1

Specific Pathogens and Their Clinical Presentations

Animal Bites

The predominant pathogens reflect the animal's oral flora: 1

• Pasteurella species (especially P. multocida): Present in 75% of cat bites and 50% of dog bites, causes rapid-onset cellulitis within 24 hours 1
• Capnocytophaga canimorsus: Can cause fatal sepsis, particularly in asplenic or cirrhotic patients 1
• Staphylococcus aureus (including MRSA) and Streptococcus species: Common secondary invaders 1
• Anaerobes (Fusobacterium, Prevotella, Bacteroides, Porphyromonas): Present in 65% of cat bites and 50% of dog bites, associated with abscess formation 1

Human Bites

Human bite infections have distinct bacteriology: 1

• Streptococci (especially viridans): Present in 80% of wounds 1
• Staphylococcus aureus: Present in 40% of wounds 1
• Eikenella corrodens: Present in 30% of wounds, a gram-negative facultative anaerobe 1
• Anaerobes: Present in 60% of cases, usually polymicrobial 1

Viral Transmission Risk

Human bites specifically carry risk of viral transmission: 1

• Hepatitis B and C
• HIV
• Herpes simplex virus

Post-exposure prophylaxis should be considered in every case of human bite 1

Non-Infectious Complications to Observe

Beyond infection, monitor for: 1

• Nerve injury or severance - assess sensory and motor function
• Tendon injury or severance - test range of motion
• Fractures - especially with crush injuries
• Vascular injury and bleeding
• Post-traumatic arthritis - long-term complication

Critical Timing Considerations

The time elapsed from bite to presentation affects infection risk: 1

• Wounds presenting <24 hours: Higher benefit from prophylactic antibiotics in high-risk cases 1
• Wounds presenting ≥24 hours without infection signs: Antibiotics generally not indicated 1
• Follow-up within 24 hours is essential for all bite wounds to reassess for developing infection 1

Special Populations Requiring Enhanced Monitoring

These patients warrant closer observation for complications: 1

• Immunocompromised individuals
• Asplenic patients (risk of Capnocytophaga sepsis)
• Advanced liver disease
• Pre-existing edema of affected area
• Patients with prosthetic devices or implants