human bites or bite

Last edited 02/2023 and last reviewed 02/2023

• human 'bites' may occur as the result of violent injury (e.g. injury to the clenched fist from a punch to the mouth) or 'love bites', or in care settings for children or people with learning disabilities (1)
• the majority human bites are on the fingers or hands but other common sites include the neck, breasts and genitalia
  • about 30% of clenched-fist injuries lead to deep lacerations and infection in tendons, bone, or other tissues remote from the puncture site, which is particularly likely if there is a delay of more than 24 hours before the person seeks medical attention
  • bacterial infection that often contaminate human bites include:
    • streptococci
    • Staphylococcus aureus
    • Haemophilus spp
    • Bacteroides
    • Fusobacterium spp and other anaerobes
    • Eikenella corrodens, a slow-growing Gram-negative bacillus
  • transmission of viruses (e.g. hepatitis B, hepatitis C, HIV) following human bites is much less common

Should all bites be treated with prophylactic antibiotics?

• NICE suggested that " if a human bite has not broken the skin, antibiotic prophylaxis should not be offered. If it has broken the skin and drawn blood, antibiotic prophylaxis should be offered... for people with a human bite that has broken the skin but not drawn blood, antibiotic prophylaxis is not routinely needed. However, they agreed that it can be considered for bites in high-risk areas or in people at risk of a serious wound infection because of a comorbidity.."(2)

General wound closure considerations (3)

• small wounds
  • may be left open to heal by secondary intention with daily non-stick dressing changes until the skin has re-epithelialised
• gaping wounds
  • can be approximated and closed after copious irrigation and debridement
• wounds to the face from any animal
  • can be closed (for cosmesis; the face has no higher risk of infection than elsewhere)
• feline (cat) bite
  • should avoid closing all non-facial wounds
• canine (dog) bites
  • majority can be closed except in the hands or feet, where infection risk is much higher
• human bites
  • should avoid closing non-facial wounds or facial wounds more than 24 hours after injury
  • requires follow up with a plastic surgeon
• puncture wounds
  • have an especially high risk of infection
  • should let all puncture wounds heal by secondary intention (after irrigation)

Key points (4):

• offer an antibiotic for a human or animal bite if there are symptoms or signs of infection, such as increased pain, inflammation, fever, discharge or an unpleasant smell. Take a swab for microbiological testing if there is discharge (purulent or non-purulent) from the wound
• do not offer antibiotic prophylaxis if a human or animal bite has not broken the skin
• Human bite:
  • offer antibiotic prophylaxis if the human bite has broken the skin and drawn blood
  • consider antibiotic prophylaxis if the human bite has broken the skin but not drawn blood if it is in a high-risk area or person at high risk
• Cat bite:
  • offer antibiotic prophylaxis if the cat bite has broken the skin and drawn blood
  • consider antibiotic prophylaxis if the cat bite has broken the skin but not drawn blood if the wound could be deep
• Dog or other traditional pet bite (excluding cat bite)
  • do not offer antibiotic prophylaxis if the bite has broken the skin but not drawn blood
  • offer antibiotic prophylaxis if the bite has broken the skin and drawn blood if it has caused considerable, deep tissue damage or is visibly contaminated (for example, with dirt or a tooth)
  • consider antibiotic prophylaxis if the bite has broken the skin and drawn blood if it is in a high-risk area or person at high risk
• *course length can be increased to 7 days (with review) based on clinical assessment of the wound

Reference:

1. Drug and Therapeutics Bulletin (2004); 42:65-72.
2. NICE (November 2020). Human and animal bites: antimicrobial prescribing
3. Colmers-Gray I N, Tulloch J S, Dostaler G, Bai A D. Management of mammalian bites BMJ 2023; 380 :e071921 doi:10.1136/bmj-2022-071921
4. Public Health England (June 2021). Managing common infections: guidance for primary care