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Bites - human and animal - Management
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Overview of management

  • Perform a detailed assessment. Assess the circumstances in which the bite occurred and determine whether there is any damage to underlying structures.
  • Determine whether the person is at increased risk of the wound becoming infected either due to the nature of the bite or a pre-existing medical condition.
  • Assess whether or not the wound is infected.
  • For human bites: assess the risk of acquiring a blood-borne virus infection, (such as hepatitis B or C, or HIV) and seek immediate advice regarding post-exposure prophylaxis if the person is at risk.
  • For animal bites: assess the risk of rabies and seek immediate advice regarding post-exposure prophylaxis if the person is at risk.
  • Clean the wound thoroughly.
  • Give tetanus prophylaxis where appropriate.
  • Prescribe analgesics if required.
  • Refer anyone with a wound that is at high risk of complications, or who needs debridement, closure, or reconstructive surgery.
  • Prescribe prophylactic antibiotics to:
    • All people with a human bite.
    • People with animal bites who are at high risk of infection.
  • Treat any wound that has become infected with a 7-day course of antibiotics.

How do I manage a human bite?

How should I assess someone with a human bite?

  • Document how and when the bite occurred.
  • Examine the bite, and document its location, appearance, and any damage to underlying structures (e.g. arteries, nerves, tendons, joints). For a bite affecting the hand also document whether it is an occlusal injury inflicted by actual biting, or a clenched fist injury.
  • Determine whether the person is at increased risk of the wound becoming infected, either due to the nature of the bite or due to a medical condition (e.g. diabetes, immunosuppressed status).
  • Assess whether the wound is infected. The following may be present: redness, swelling, serosanguinous or purulent discharge, pain, localized cellulitis, lymphadenopathy, or fever.
  • Assess tetanus status, drug history and any known allergies.
  • Assess whether there is a risk of acquiring a blood-borne viral infection (e.g. hepatitis B or C, or HIV).
    • In most cases the status of the biter will not be known and it is often not practical to obtain a blood sample for testing. There is a higher risk of acquiring a blood-borne virus if:
      • The biter is known to be HIV positive, hepatitis B surface antigen (HBsAg) positive, or hepatitis C positive.
      • The biter is likely to be a high risk person, such as an intravenous drug user.
    • Assess the status of the person who has been bitten:
      • Ask if they are known to be HIV positive, hepatitis B surface antigen (HBsAg) positive, or hepatitis C positive.
      • Check their vaccination status for hepatitis B.
  • It is essential to obtain an X-ray in people with the following:
    • Clenched fist injuries to exclude the presence of teeth or dental fragments, and rule out bone damage.
    • Crush injuries, suspected fracture, the possibility of a foreign body in the wound.
  • Although rare, suspect child maltreatment if there is a report or appearance of a human bite mark that is thought unlikely to have been caused by a young child.
Clarification / Additional information
  • Assess and document under what circumstances the bite occurred:
    • Who was bitten by whom.
    • When the bite occurred.
    • Whether the skin was broken.
    • The nature of the bite (i.e. occlusal or clenched fist).
    • Any risk factors for infection.
    • Consider existing infection or other medical conditions in both the biter and the person who has been bitten.
    • Tetanus status.
  • Note and document the following [Griego et al, 1995; Taplitz, 2004; HPA, 2005b; Morgan and Palmer, 2007] (record both positive and negative findings as there may be future litigation) [Taplitz, 2004]:
    • The location of the wound. Photographs or diagrams may be useful.
    • The size and depth of the injury.
    • The type of wound (e.g. penetrating or crush injury).
    • The degree of crush injury, devitalized tissue, nerve or tendon damage, and involvement of bones, joints, or blood vessels.
    • The range and movement of any adjacent joints.
    • The presence or absence of signs of infection.
    • Any lymphadenopathy.
    • The presence of any foreign bodies (e.g. teeth).
    • Any signs of infection.
    • Facial bites: perform an intraoral examination to exclude cheek lacerations with an intraoral communication [Morgan, 2005].
  • If the biter has not been tested for blood-borne virus infection then treat their status as unknown unless there is a very good reason to do otherwise (e.g. they have an AIDS-defining illness).
Basis for recommendation
  • These recommendations are based on advice from the Health Protection Agency [HPA, 2005b] and expert opinion on the management of bites [Griego et al, 1995; Taplitz, 2004; Morgan, 2005].
  • The recommendation on when to suspect child maltreatment is based on advice from the National Institute for Health and Clinical Excellence [NICE, 2009].

When should I refer someone with a human bite?

  • Refer to secondary care:
    • Penetrating wounds involving arteries, joints, nerves, muscles, tendons, bones, or the central nervous system. Note: penetrating bites to the hands or feet are at particular risk of infection and serious complications.
    • Facial wounds (excluding very minor wounds).
    • Bites where there is a possibility of a foreign body (e.g. a tooth) in the wound.
    • Devitalized wounds where debridement is required.
    • Bites where the severity of the injury is difficult to assess.
    • People with severe cellulitis, or with infected bite wounds that are not responding to treatment, or who are systemically unwell.
    • People with an increased risk of infection — including those with diabetes or cirrhosis, those who are immunocompromised, and asplenic individuals (especially if they are not taking prophylactic penicillin).
    • Injuries requiring reconstructive surgery.
    • Bites to poorly vascularized areas e.g. ear cartilage/nose cartilage.
  • If adult bites have been inflicted on a child, consider child protection issues. Follow local policies for referral of children considered at risk.
Basis for recommendation

How should a human bite wound be cared for initially?

  • If the wound has just occurred, encourage it to bleed, unless it is already bleeding freely.
  • Irrigate thoroughly with warm, running water.
  • Wound closure is rarely advised in primary care.
  • Advise analgesia (paracetamol or ibuprofen) for pain relief, if required.
  • Prescribe prophylactic antibiotics for all human bite wounds under 72 hours old even if there is no sign of infection.
  • Consider if tetanus prophylaxis is required.
  • Where body tissue has been torn off as a result of a bite, wrap any torn off parts (e.g. part of an ear) in clean tissue and store in a plastic bag surrounded by ice for transport to hospital.
    • Management does not typically include reapplication of removed tissue.
  • Seek immediate advice from a consultant in infectious diseases for anyone considered to be at risk of HIV or hepatitis B.
Basis for recommendation
  • These recommendations are based on expert opinion from the published medical literature [HPA, 2005b].
  • The wound should be irrigated thoroughly to remove dirt and bacteria and to minimize the risk of infection.
  • Antiseptic cleansers are not necessary and there is some concern that they damage tissue and delay wound healing [Hollander and Singer, 1999].
  • If a bite is 72 hours old and there is no sign that it has become infected, the risk of infection is likely to be low and prophylactic antibiotics are probably not of value. 

When should I close a human bite wound?

  • Bite wounds suitable for management in primary care do not usually require closure.
  • Referral to Accident and Emergency for further assessment and management is usually indicated if wound closure is thought to be necessary.
  • If referral to Accident and Emergency is not possible, the types of wounds that may be considered for closure include:
    • Fresh bite wounds (e.g. less than 6 hours old) where there are no risk factors for infection.
    • Bite wounds which are between 6 and 24 hours old where there are no risk factors for infection. However this is controversial and currently there is no consensus of opinion.
  • Allow the following bite wounds to heal without formal closure:
    • Bite wounds over 24 hours old.
    • Infected bite wounds.
    • Deep puncture wounds.
    • Bites to the hands and feet.
Basis for recommendation
  • These recommendations are based on expert opinion from the published medical literature [DTB, 2004; Taplitz, 2004; Brook, 2005; Richardson, 2006; Kravetz, 2007]. Wound closure is a controversial issue. CKS did not identify any randomized controlled trials or systematic reviews that assessed primary closure or delayed closure for human bites, however:
    • There is general agreement that infected wounds and those first seen more than 24 hours after the bite occurred should be left open.
    • Some experts recommend consideration of wound closure after irrigation and debridement in patients presenting less than 6 hours after the injury if there is no visible evidence of infection.
    • For bite wounds in anatomic regions where there are significant cosmetic concerns, such as the face, a primary closure approach by a plastic surgeon or other expert is often undertaken to prevent significant scarring.
    • Wounds with a high risk of complications or infection, such as hand wounds, are generally left open even in patients who present early. When closure is deemed appropriate, wound edges can be approximated but must still allow for drainage. If a joint or tendon is thought to be involved refer to orthopaedics or plastic surgery.

When should I give tetanus prophylaxis?

  • Give tetanus prophylaxis as follows:
    • Person fully immunized, i.e. has received five doses of vaccine at appropriate intervals: tetanus booster not needed. Consider giving human tetanus immunoglobulin for tetanus-prone wounds where the risk of infection is especially high, e.g. those contaminated with manure or extensive devitalized tissue.
    • Primary immunization complete, boosters incomplete but up-to-date: tetanus booster not needed but may be given if booster is due and it is convenient to give now. Consider giving human tetanus immunoglobulin for tetanus-prone wounds where the risk of infection is especially high, e.g. those contaminated with manure or extensive devitalized tissue.
    • Primary immunization incomplete, or boosters not up-to-date: give tetanus booster and further doses as needed to complete the recommended schedule (note: if the primary course is interrupted it should be resumed but not repeated). Add human tetanus immunoglobulin if it is a tetanus-prone wound (defined as: a puncture wound; a significant degree of devitalized tissue; contaminated with soil or manure; containing foreign bodies; compound fractures; clinical signs of sepsis; wounds or burns sustained more than 6 hours before surgical treatment). Note: inject tetanus vaccine and immunoglobulin at different sites.
    • Not immunized or immunization status uncertain: give an immediate dose of vaccine. Add human tetanus immunoglobulin if it is a tetanus-prone wound (see above). Arrange further doses of tetanus vaccine as needed to complete the recommended five-dose schedule.
Clarification / Additional information
  • A total of five doses of tetanus vaccine, administered at the appropriate intervals, is considered to give lifelong immunity.
  • Vaccinate the person with a combined tetanus vaccine e.g. tetanus/diphtheria/inactivated polio vaccine, as tetanus vaccine is only available in a combined preparation.
Basis for recommendation
  • These recommendations are based on expert opinion from the Department of Health [DH, 2006a].

How do I treat a human bite that has become infected?

  • Send pus or a deep wound swab for culture, before cleaning the wound. State on the form that the swab is from an infected human bite.
  • Treat empirically for 7 days with oral antibiotics.
  • Admit anyone who has a severe infection or who is systemically unwell since intravenous antibiotics may be required.
Basis for recommendation
  • These recommendations are based on expert opinion from the published literature [HPA, 2005b; Kravetz, 2007]. CKS found no good quality randomized controlled trials that assessed the use of antibiotics for people with infected wound bites. However they are generally believed to be effective.

Which antibiotic should I give to someone with a human bite?

  • For both prophylaxis and treatment of an infected human bite prescribe a 7-day course of co-amoxiclav.
  • For people who are allergic to penicillin prescribe a 7-day course of:
    • Metronidazole plus doxycycline, or
    • Metronidazole plus erythromycin, or
    • Metronidazole plus clarithromycin.
Basis for recommendation
  • These recommendations are based on expert opinion published in the medical literature [HPA, 2005b; HPA, 2006a].
  • There is limited evidence that antibiotics prevent infections after a human bite.
  • More than 42 different species of bacteria have been isolated from the human mouth, and up to 190 if gingivitis or periodontitis are present. The most common organisms in human bites include Streptococcus spp, Staphylococcus aureus, Haemophilus spp, Eikenella corrodens, and Bacteroides spp and other anaerobes. E. corrodens has been found in 25% of human bites to the hand [Smith et al, 2000; HPA, 2005b; Morgan, 2005].
  • Co-amoxiclav:
    • Co-amoxiclav is recommended because it is a broad-spectrum antibiotic and effective against the most commonly isolated organisms from human bites including alpha- and beta-haemolytic streptococci, S. aureus, S. epidermis, corynebacteria, and E. corrodens.
  • Metronidazole plus erythromycin or clarithromycin:
    • Metronidazole (in addition to tetracyclines or erythromycin) covers beta-lactamase-producing anaerobes.
    • Erythromycin has good activity against staphylococci and streptococci (the most common pathogens).
    • Clarithromycin may be more suitable if erythromycin cannot be tolerated due to adverse effects.

How should I manage someone who may be at risk of a blood-borne viral infection?

  • Seek immediate advice from a consultant in infectious diseases for anyone considered to be at risk of HIV or hepatitis B. Consider all people to be at risk unless the current status of the biter is known (rare).
  • If post-exposure prophylaxis (PEP) is needed:
    • PEP for HIV should be started at soon as possible.
    • Seek advice about the most appropriate PEP regimen for hepatitis B, see Table 1.
    • Reassure the person that the risk of acquiring hepatitis or HIV from a bite is very small, even if the assailant is known to be infected.
  • Arrange sequential testing to check for seroconversion (see Testing for seroconversion of virus).
Table 1. Hepatitis B vaccine prophylaxis for significant exposure (e.g. a bite from a high risk individual).
Hepatitis B vaccination status of person exposed
HBsAg positive source
HBsAg status unknown
HBsAg negative source
Unvaccinated
Give an accelerated* or hyperaccelerated† course of hepatitis B vaccine and one dose of hepatitis B immunoglobulin
Give an accelerated or hyperaccelerated course of hepatitis B vaccine
Initiate course of hepatitis B vaccine
Received one dose of hepatitis B vaccine pre-exposure
Give an accelerated* or hyperaccelerated† course of hepatitis B vaccine and hepatitis B immunoglobulin
Give an accelerated or hyperaccelerated course of hepatitis B vaccine
Finish course of hepatitis B vaccine
Received two or more doses of hepatitis B vaccine
Give one dose of hepatitis B vaccine followed by one dose one month later
Give one dose of hepatitis B vaccine
Consider booster dose of hepatitis B vaccine
Known responder to hepatitis B vaccine (anti HBs > 10 miU/mL)
Consider booster dose of hepatitis B vaccine
Consider booster dose of hepatitis B vaccine
Consider booster dose of hepatitis B vaccine
Known non responder to hepatitis B vaccine (anti HBs < 10 miU/mL 2–4 months post immunization)
Give one dose of hepatitis B immunoglobulin and consider giving a booster dose of hepatitis B vaccine
Give one dose of hepatitis B immunoglobulin and consider giving a booster dose of hepatitis B vaccine
Consider giving a booster dose of hepatitis B vaccine. Do not give a course of hepatitis B immunoglobulin
* An accelerated course of vaccine consists of doses spaced at 0, 1, and 2 months. A booster dose may be given at 12 months to those at continuing risk of exposure to HBV.
† A hyper-accelerated course of vaccine may be offered by some Occupational Health Departments. This consists of doses at 0, 7, and 21 days with booster dose at 6 or 12 months.
Data from: [HPA, 2005b]
Clarification / Additional information
  • It is usually very difficult to assess whether or not a person is at risk of contracting HIV, or hepatitis B or C. For information on how to assess whether the person who has been bitten is at risk of acquiring a blood-borne virus, see Assessing someone with a human bite. Always err on the side of caution and seek immediate advice from a specialist if you consider there is any risk of infection.
  • In people who are at high risk of a blood-borne virus infection, explain that it is important to take blood to store in the laboratory in case future follow-up tests are positive.
  • When taking blood from a person who is at high risk of a blood-borne virus infection:
    • Explicit valid consent from the person, or from their legal representative if appropriate, should be obtained before the test. Consent is needed both for taking and testing blood, and for checking results against archived samples.
    • Obtain a 10 mL clotted sample from the person who has been bitten for archiving in the laboratory.
    • Where practical, a sample should be obtained from the biter for testing for hepatitis B surface antigen (HBsAg), HIV, and hepatitis C.
Basis for recommendation
  • These recommendations are based on expert opinion from the Health Protection Agency.
  • The risk of transmission of HIV from a human bite is unknown but is likely to be small [HPA, 2005b]. In the rare cases when HIV transmission has occurred, bloody saliva has been present [Morgan, 2005]. Many reports are case studies [Vidmar et al, 1996; Khajotia and Lee, 1997; Pretty et al, 1999]. The risk is likely to be increased if [Pretty et al, 1999]:
    • Blood is present in the oral cavity.
    • The bite breaks the skin.
    • The bite is associated with a previous injury.
    • The biter had a deficiency in anti-HIV salivary elements.
  • There are case reports that hepatitis B may be transmitted by a human bite [Stornello, 1991; Hui et al, 2005].
  • There are case reports suggesting that hepatitis C may be transmitted by a human bite [Dusheiko et al, 1990; Figueiredo et al, 1994]. The Health Protection Agency states that hepatitis C appears to be transmitted more easily than HIV [HPA, 2005b].

How do I test for seroconversion of a blood-borne virus?

  • Obtain valid consent for all tests.
  • If any of the tests are positive, seek advice from a consultant in infectious diseases for further management.
    • Blood should have been taken from the victim at the time of the incident and archived.
Table 1. Testing for hepatitis C, hepatitis B, and HIV after potential exposure.
Time
Hepatitis C
Hepatitis B
HIV
6 weeks
Polymerase chain reaction (PCR)
Surface antigen
Antigen/antibody combined test
3 months
Polymerase chain reaction (PCR) and antibody
Surface antigen
Antigen/antibody combined test
6 months
Antibody
Surface antigen (surface antibody)*
Antigen/antibody combined test
* HB surface antibody only needed at 6 months if vaccination only started at injury.
Data from: [HPA, 2005b]
Basis for recommendation
  • This recommendation is based on expert opinion from the Health Protection Agency.

What follow-up is needed for someone who has had a human bite?

  • This follow-up advice only applies to people who have not been referred to hospital (i.e. are being managed in primary care).
  • If the bite wound is not infected — advise the person to check for signs of infection and if these develop to attend urgently for review.
  • If the wound is infected — review at 24 and 48 hours to ensure the infection is responding to treatment. Advise the person to attend urgently for review if the infection worsens or if they feel increasingly unwell.
  • For follow-up of people who are at high risk of a blood-borne virus see Managing risk of a viral infection.
Basis for recommendation
  • These recommendations are based on pragmatic advice and expert opinion from the Health Protection Agency [HPA, 2005b].

How do I manage an animal bite?

How do I assess someone with an animal bite?

  • Document how and when the bite occurred.
  • Examine the bite, and document its location, appearance, and any damage to underlying structures such as arteries, nerves, tendons, or joints.
  • Determine whether the person is at increased risk of the wound becoming infected, either due to the nature of the bite, or due to a medical condition (e.g. diabetes, immunosuppressed status).
  • Assess whether the wound is infected. The following may be present: redness, swelling, serosanguinous or purulent discharge, pain, localized cellulitis, lymphadenopathy, fever.
  • Assess tetanus status, drug history and any known allergies.
  • Assess the risk of acquiring rabies.
  • Send cultures for aerobic and anaerobic bacteria if the wound appears to be infected. Take samples from the deepest part of the wound, after topical decontamination, but before cleaning it thoroughly.
  • It is essential to obtain an X-ray in people with the following:
    • Penetrating scalp injuries in children. A small scalp puncture wound may indicate anchoring of teeth to the cranium during shaking, and it is important to identify underlying cranial injury or facial fractures.
    • Crush injuries, suspected fracture, foreign body.
  • Although rare, consider the possibility of child neglect if there is a report or appearance of an animal bite on a child who has been inadequately supervised.
Clarification / Additional information
  • Assess and document under what circumstances the bite occurred:
    • When and in what country did the bite occur?
    • What sort of animal bit the person?
    • Was the attack provoked?
    • Was the animal domestic or wild?
    • The nature of the bite — its site, number, depth, and amount of tissue destruction.
    • Any risk factors for infection.
    • Does the person have any other medical conditions?
    • What is the tetanus status of the person?
  • Record both positive and negative findings as there may be future litigation [Taplitz, 2004], including [Griego et al, 1995; Taplitz, 2004; Morgan and Palmer, 2007]:
    • The location of the wound. Photographs or diagrams may be useful.
    • The size and depth of the injury.
    • The type of wound (e.g. penetrating or crush injury).
    • The degree of crush injury, devitalized tissue, nerve or tendon damage, and involvement of bones, joints, or blood vessels.
    • The range and movement of any adjacent joints.
    • The presence or absence of signs of infection.
    • Any lymphadenopathy.
    • The presence of any foreign bodies (e.g. teeth) in the wound.
    • Any signs of infection.
    • Facial bites: perform an intraoral examination to exclude cheek lacerations with an intraoral communication [Morgan, 2005].
  • Assess the risk of rabies:
    • In which country was the person bitten?
      • If the person was bitten in the UK there is no risk of rabies unless the bite was from a bat.
      • If the person was bitten abroad use the Health Protection Agency country by country risk chart (pdf). Note that the origin of the animal is important. Was the animal non-indigenous or recently imported? Was it a terrestrial animal or a bat?
    • What was the type of exposure?
      • Use the Health Protection Agency Duty Doctor Rabies protocol (pdf), taking into account the site and severity of the exposure, whether the bite/scratch was provoked, the current state of health of the animal (if known), and its ownership. Determine the tetanus and rabies immunization status of the dog or cat, if known. People are at risk not only if they have sustained major bites, but also if they have had minor bites (e.g. bites through clothed areas of the arms, trunk, or legs), licks to the mucosa, or licks to non-intact skin (e.g. if there are scratches or abrasions).
    • What is the immune status of the person bitten?
      • Ask whether the person had a primary course of rabies vaccination or any boosters in the past, and if so when this was.
Basis for recommendation
  • The basis for this recommendation is advice from the Health Protection Agency Centre for Infections [HPA, 2008], and expert opinion on the management of bites [Griego et al, 1995; Taplitz, 2004; Morgan, 2005; Villani, 2006; Morgan and Palmer, 2007].
  • Consider the possibility of rabies in anyone who has been bitten by a bat in the UK [HPA, 2006e].
  • Consider the risk of rabies in anyone who has sustained a bite or scratch from a dog or cat whilst abroad [de Medeiros and Saconato, 2003; HPA, 2008]. The main host is usually a dog (in 99% of all human deaths from rabies) but other hosts include foxes, coyotes, wolves, jackals, cats, skunks, raccoons, mongooses, bats, and other biting animals [WHO, 1999].
  • The recommendation on when to consider child neglect is based on advice from the National Institute for Health and Clinical Excellence [NICE, 2009].

When should I refer someone with an animal bite?

  • Refer to secondary care:
    • Penetrating wounds involving arteries, joints, nerves, muscles, tendons, bones, or the central nervous system. Note: penetrating bites to the hands or feet are at particular risk of infection and serious complications.
    • Facial wounds (excluding very minor wounds).
    • Bites where there is a possibility of a foreign body (e.g. a tooth) in the wound.
    • Wounds which might benefit from closure.
    • Devitalized wounds where debridement is required.
    • Bites where the severity of the injury is difficult to assess.
    • People with severe cellulitis, or with infected bite wounds that are not responding to treatment, or who are systemically unwell.
    • People with an increased risk of infection — including those with diabetes or cirrhosis, those who are immunocompromised, and asplenic individuals (especially if they are not taking prophylactic penicillin).
    • Bites that might need reconstructive surgery.
    • Children with scalp wounds (for X-ray).
    • Bites to poorly vascularized areas eg ear cartilage/nose cartilage.
  • If an animal has bitten a child, consider the possibility of poor parenting and supervision. Follow local policies for referral of children considered at risk.
  • If there is a possibility that the person has been exposed to rabies, seek immediate advice from the Virus Reference Department of the Health Protection Agency. For more information see Managing someone at risk of rabies.
Basis for recommendation

How should an animal bite be cared for initially?

  • If possible remove any foreign bodies (e.g. teeth) from the wound.
  • If the wound has just occurred, encourage it to bleed, unless it is already bleeding freely.
  • Irrigate thoroughly with warm, running water.
  • Wound closure is rarely advised in primary care. For more information see When to close an animal bite wound.
  • Advise analgesia (ibuprofen or paracetamol) for pain relief, if required.
  • Prescribe prophylactic antibiotics if the wound is less than 48 hours old and the risk of infection is high.
  • Consider if tetanus prophylaxis is required.
Basis for recommendation
  • These recommendations are based on expert opinion from the published medical literature [HPA, 2005b; HPA, 2006c; Morgan and Palmer, 2007].
  • Although tetanus after animal bites is rare, all guidelines in common use advise tetanus prophylaxis, with immunoglobulin and toxoid to be administered to patients with a history of two or fewer immunizations.
  • Irrigation of the wound removes dirt and bacteria, minimizing the risk of infection.
  • There is no evidence to support irrigating a deep penetrating wound with normal saline using a needle or catheter, but it is common practice.
  • Antiseptic cleansers are not necessary, and there is some concern that they damage tissue and delay wound healing [Hollander and Singer, 1999].

When should I close an animal bite wound?

  • Minor bite wounds suitable for management in primary care do not usually require closure.
  • Referral to Accident and Emergency for further assessment and management is usually indicated if wound closure is thought to be necessary.
  • The type of wounds that may be considered for closure include:
    • Fresh bite wounds (e.g. less than 6 hours old) where there are no risk factors for infection.
    • Bite wounds that present between 6 and 24 hours where there are no risk factors for infection. However this is controversial and currently there is no consensus of opinion.
  • Allow the following bite wounds to heal without formal closure:
    • Bite wounds over 24 hours old.
    • Infected bite wounds.
    • Deep puncture wounds.
    • Bites to the hands and feet.
Basis for recommendation
  • These recommendations are based on expert opinion from the published medical literature [DTB, 2004; Taplitz, 2004; Brook, 2005; Richardson, 2006; Kravetz, 2007]. Wound closure is a controversial issue. CKS identified one small randomized controlled trial that compared primary wound closure with leaving a bite wound open [Maimaris and Quinton, 1988]. There was no difference between the groups in the incidence of infection. However:
    • There is general agreement that infected wounds, and those first seen more than 24 hours after the bite, should be left open.
    • Some experts recommend consideration of wound closure, after irrigation and debridement, in patients presenting less than 6 hours after the injury, if there is no visible evidence of infection.
    • For bite wounds in anatomic regions where there are significant cosmetic concerns, such as the face, a primary closure approach by a plastic surgeon or other expert is often undertaken to prevent significant scarring.
    • Wounds with a high risk of complications or infection, such as hand wounds, are generally left open even in patients who present early. When closure is deemed appropriate, wound edges can be approximated but must still allow for drainage. If a joint or tendon is thought to be involved, an orthopaedic or plastic surgery consultation should be obtained.

Should I give antibiotic prophylaxis to someone with an animal bite?

  • Prescribe antibiotics for:
    • All cat bites, animal bites to the hand, foot, and face; puncture wounds; wounds requiring surgical debridement; wounds involving joints, tendons, ligaments, or suspected fractures.
    • Wounds that have undergone primary closure.
    • People who are at risk of serious wound infection (e.g. those who are diabetic, cirrhotic, asplenic, or immunosuppressed).
    • People with a prosthetic valve or a prosthetic joint.
  • Antibiotics are not generally needed if the wound is more than 2 days old and there is no sign of local or systemic infection.
Basis for recommendation
  • These recommendations are based on published expert opinion [Dire, 1992; Cummings, 1994; Smith et al, 2000; HPA, 2006c; Morgan and Palmer, 2007].
  • Limited evidence from a Cochrane systematic review (only one randomized controlled trial used co-amoxiclav) suggests that antibiotic prophylaxis reduces the incidence of infections from cat bites, and from any type of bite wounds to the hand.
  • Antibiotic prophylaxis following animal bites should be employed selectively, being reserved for the bites most likely to become infected, such as when adequate debridement cannot be achieved, and in immunocompromised people at high risk of infection [HPA, 2006c].
    • High-risk patients with more justification for antibiotic prophylaxis include those with previous mastectomy, prosthetic joints, diabetes, immunosuppression, cirrhosis, steroid therapy, and splenectomy.

Which antibiotic should I use for someone with an animal bite?

  • For prophylaxis and treatment of an infected animal bite prescribe a 7–day course of co-amoxiclav.
  • For people who are allergic to penicillin prescribe:
    • Metronidazole plus doxycycline, or
    • Metronidazole plus oxytetracycline.
  • For children under 12 years old who are allergic to penicillin seek advice from a microbiologist.
  • Do not use erythromycin alone for prophylaxis or treatment of bite wounds.
  • For animal not covered in this guidance (e.g. pigs) seek specialist advice for the most appropriate antibiotic.
Basis for recommendation
  • These recommendations are based on published expert opinion from the Health Protection Agency [HPA, 2006a].
  • Co-amoxiclav is recommended as it is a broad-spectrum antibiotic and effective against most bacteria isolated from domestic animal bites.
  • Doxycycline/oxytetracycline plus metronidazole are recommended as:
    • Doxycycline and oxytetracycline have good activity against Pasteurella species (the most common pathogen), staphylococci, and streptococci [Smith et al, 2000; Talan et al, 2003].
    • Metronidazole is active against beta-lactamase-producing anaerobes.
  • Most infections that develop from dog and cat bites are caused by several organisms, with a mean of 2.8 to 3.6 bacterial species per wound culture, including an average of one anaerobic species per wound [Griego et al, 1995].
  • One study of infected cat and dog bites found that the most commonly isolated bacteria was Pasteurella (57% of dog bites and 75% of cat bites). Other common aerobes included streptococci, staphylococci, moraxella, and neisseria. Common anaerobes included fusobacterium, bacteroides, porphyromonas, and prevotella [Talan et al, 1999].
    • Pasteurella multocida is a Gram-negative pathogen that causes a rapid intense inflammatory response [Morgan, 2005; HPA, 2006b; Morgan and Palmer, 2007]:
      • It is found in dogs, cats, rabbits, chickens, turkeys, cattle, swine, and rodents.
      • It is is the most likely pathogen in an infected bite by a dog or cat presenting within 12 hours of the bite.
      • Complications include abscesses, cellulitis, and joint infections.
      • If septicaemia develops, the mortality may be as high a 30%.
      • Rarely it may cause pneumonic or lung abscesses in people with underlying pulmonary disease.
      • It is resistant to erythromycin and flucloxacillin.
      • It may cause tenosynovitis in hand bites and may lead to irreparable damage and amputation.
  • Co-amoxiclav is recommended because it is effective against most bacteria isolated from domestic animal bites. Penicillin will not cover all Staphylococcus aureus infections, or infections caused by anaerobes.
  • Metronidazole (in addition to tetracyclines) covers beta-lactamase-producing anaerobes.
  • Erythromycin should never be used alone in treating bite wounds — more than 80% of P. multocida are resistant, and serious clinical failures including meningitis have been documented following erythromycin treatment.

How do I treat an animal bite that has become infected?

  • Send a pus or deep wound swab for culture (state on the form that the swab is from an infected animal bite).
  • Treat empirically with oral antibiotics for 7 days.
  • Admit anyone who has a severe infection or who is systemically unwell since intravenous antibiotics may be required.
Basis for recommendation
  • These recommendations are based on expert opinion from the published literature [HPA, 2006c]. CKS found no good quality randomized controlled trials that assessed the use of antibiotics for people with infected wound bites. However they are generally believed to be effective.

What advice should I give about avoidance of future bites?

  • Avoid running or screaming in the presence of a dog, as dogs have a tendency to chase moving objects.
  • Do not greet a dog with an outstretched hand.
  • Do not pet a dog without letting it sniff you first.
  • Avoid humanising the dog (e.g. allowing it to sleep on the furniture, beg for food), and do not hug or kiss it, as this makes it more difficult for the dog to distinguish between animal and master, and may increase the risk of biting.
Basis for recommendation
  • This advice is based on expert opinion from the published literature [Presutti, 2001].
  • Canine aggressiveness may stem from inadequate socialisation, fear, protection of territory, dominance behaviour, jealously, or over breeding [Brogan et al, 1995]:
    • Dominance aggression usually occurs in relation to people who are well known to the dog, and most often happens in familiar surroundings.
    • Stray dogs tend to be more wary and are less likely to be aggressive.

How do I manage someone who may be at risk of contracting rabies?

  • Discuss the need for post-exposure prophylaxis urgently with the Virus Reference Department of the Health Protection Agency (HPA, telephone 020 8327 6017).
    • Manage according to the risk of rabies. The combination of human rabies immunoglobulin and rabies vaccine is recommended for bite exposure, regardless of the interval between exposure and initiation of treatment [HPA, 2008].
  • Everyone who has been bitten by a bat in the UK needs post-exposure prophylaxis urgently. The HPA advises that, to ensure consistency of advice: for all unequivocal exposures to bats (such as bites which are of a nature to be a possible rabies risk) post-exposure prophylaxis should be with rabies immunoglobulin and five doses of vaccine. If the exposure is uncertain (the person can not confirm a bite), then vaccination alone may be considered [HPA, 2008].
  • Complete a Rabies Advice Record Form (even if you decide that no treatment is required). Record the number of doses of human rabies immunoglobulin (if required) and the number of doses of vaccine required. Phone the Virus Reference Department (VRD) to verify the decision or if you require further advice. Send all completed forms to the Rabies secretary, VRD Office, by hand or fax to 020 8200 1569 [DH, 2006b].
Basis for recommendation
  • These recommendations are based on expert opinion from the Health Protection Agency [HPA, 2008].

What follow-up is needed for someone who has had an animal bite?

  • This follow-up advice only applies to people who have not been referred to hospital (i.e. are being managed in primary care).
  • If the bite wound is not infected — advise the person to check for signs of infection and if these develop to attend urgently for review.
  • If the wound is infected — review at 24 and 48 hours to ensure the infection is responding to treatment. Advise the person to attend urgently for review if the infection worsens or if they feel increasingly unwell.
  • Follow-up for people who have needed post-exposure prophylaxis for rabies should follow the regimen advised for them by the Virus Reference Department of the Health Protection Agency.

What advice should I give to people at risk of rabies due to their occupation or travel?

  • Occupational risk: the following people who are at risk of being bitten due to their occupation should be offered pre-exposure vaccine, including rabies. For a full list of people for whom pre-exposure vaccination is recommended see the Department of Health website, Immunizations against infectious disease.
    • Those who, in the course of their work, regularly handle imported animals, for example at animal quarantine centres, zoos, research and acclimatization centres where primates and other imported animals are housed, ports (e.g. certain HM Revenue and Customs officers), and at the premises of carrying agents authorized to carry imported animals.
    • Veterinary and technical staff, including local authority dog wardens who are also inspectors.
    • People who regularly handle bats in the UK.
    • Those working abroad (e.g. veterinary staff or zoologists) who by the nature of their work are at risk of contact with rabid animals.
  • Travellers at risk: pre-exposure immunization is also recommended for some travellers, including:
    • Those living in or travelling for more than one month to rabies-enzootic areas, unless there is reliable access to prompt, safe medical care.
    • Those travelling for less than one month to enzootic areas, but who may be exposed to rabies because of their travel activities, or those who would have limited access to post-exposure medical care.
Basis for recommendation
  • These recommendations are based on guidance from the Health Protection Agency and the Department of Health [DH, 2006b; HPA, 2006e; HPA, 2008].

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