Bite wounds

CASES/YEAR
4,900,000 (US); 147,000,000 (Global)
CATEGORY
Localized Infections
AGENT TYPE
Mixed
OTHER NAMES
ACUITY
Acute-Moderate
INCUBATION
Estimated 1 to 5 days;
INITIAL SYMPTOMS
Wound <8 hours: too early for infection; Wound >8 hours: look for fever, cellulitis, drainage, and abscess; [ABX Guide]
PRECAUTIONS
"Patients with human bites should receive postexposure prophylaxis for viral hepatitis (see p. 222) and HIV (see p. 1627) as indicated by patient and attacker serostatus." [Merck Manual, p. 2941]
COMMENTS
Dog bites comprise about 80% of all bite wounds, and about 15-20% of them become infected. Antibiotics are sometimes recommended for dog bites and usually recommended after cat bites (>50% get infected) and human bites to the hand (10-15% get infected); [Harrisons, p. 115, 118] Clean wound with copious soap & water. Debride necrotic tissue. Consider prophylaxis, tetanus, rabies. (There were only 2 cases of non-bat rabies in the USA from 1990-2003.) Rare complications of animal bites are sepsis, endocarditis, meningitis, and brain abscesses. [PPID, p. 3766] "The oral flora of humans includes Eikenella corrodens, staphylococci, streptococci, and anaerobes." [Merck Manual, p. 291] For macaque monkey bites, see "B-virus meningoencephalitis." For rat bites, see "Rat-bite fever." Presumed risk of rabies from bite by dog (in developing country), raccoon, skunk, bat, or fox; see "Rabies."
DIAGNOSTIC
Culture infected wounds; HIV transmission is unlikely from human bite; Consider testing attacker for HIV and hepatitis B; Consider clenched fist injury and check for underlying damaged structures; [Merck Manual, 2940-1]
SCOPE
Global
SIGNS & SYMPTOMS
  • >arthralgia
  • >fever
  • H lymphadenopathy
  • S cellulitis or rash, circinate
  • S entry wound with lymph nodes
  • S lymphangitis
  • S pustule
  • *acute renal failure
  • *arthritis
  • *bleeding tendency
  • *brain abscess or lesion
  • *endocarditis
  • *meningitis
  • *osteomyelitis
  • *sepsis
ANTIMICROBIC

Yes

VACCINE

Yes

ENTRY
Animal Bite
SOURCE
RESERVOIR
Cats, Dogs, Monkeys, Rodents, Human, Wild Animals
RISK FACTORS
  • Handle dog or cat (bite or scratch)
  • Handle infected rodents (bite)
TREATMENT
Leave wound open if possible, approximating edges with steri-strips. For cosmetic reasons, face wounds may need to be sutured after copious irrigation (high pressure 20 mL syringe with 18 ga. needle); Elevate if extremity wound; Consider antibiotics, tetanus, and rabies. [ABX Guide] See list of 9 wounds that should be left open. Continuously elevate severe hand wounds. [Merck Manual, p. 2941]
REFERENCES FOR CASES/YEAR
1. (US) 4.5 million dog bites and 400,000 cat bites per year in US; [Fact sheets from WHO] Calculate using WHO estimates: 4.9 million bites per year in US;
2. (Global) 5 million snake bites and 10s of millions of dog bites per year; [Fact sheets from WHO]