This systematic review evaluates the scientific literature on abusive and non-abusive bites in children published up until June 2014 and reflects the findings of eligible studies. The review aims to answer the following clinical question:

1. 1. Is this an abusive bite?

A literature search was performed using a number of databases for all original articles and conference abstracts published since 1950. Supplementary search techniques were used to identify further relevant references. See Appendix 1 for full methodology including search strategy and inclusion criteria.

Potentially relevant studies underwent full text screening and critical appraisal. To ensure consistency, ranking was used to indicate the level of confidence that abuse had taken place and also for study types.

• • Of 171 studies reviewed (four foreign language articles), five studies were included^7-11

Age

• • Ranging 0-18 years for the group, as a whole
  • Four cases were aged less than 30 months
  • The fifth case was in their late teenage years

Gender

• • two boys, three girls
  • No study addressed disabled children

Influence of ethnicity and socio-economic group

• • One child noted to be white, no details on the other cases
  • No detail on socio-economic group

Details of included studies

In all included cases children had suffered physical abuse and the bite was confirmed by a forensic dentist.

• • Case 1:
    • Child noted in foster care to have a vivid discoloured bite mark to the abdomen⁷
    • Clinical photograph taken; although the photo did not contain the appropriate measuring device, it was still possible to derive the width, central ecchymotic area and lengths of linear marks from incisal edges⁷
    • Examination of three potential suspects confirmed the grandmother to be the only possible perpetrator⁷
    • This case highlights the importance of early accurate photography⁷

• • Case 2:
    • 30/12 old child with four day history of annular lesions, initially diagnosed as ringworm⁸
    • Dermatologist confirmed the lesions were bites due to their shapes and patterns⁸
    • Dental impressions excluded family members; nursery staff were suspected. This resulted in a forensic dental assessment⁸
    • This case highlights the importance of seeking further opinion and dental casts by forensic dentists⁸

• • Case 3:
    • 10/12 old child with lesions to back of the tongue, characteristic arc shape with concave surface pointing labially. This case could, therefore, not have been self induced⁹
    • Intercanine distance was consistent with an adult bite from six days earlier⁹
    • Associated injuries included multiple fractures and intracranial injury⁹
    • This case highlights the importance of noting exact contours and measurements⁹

• • Case 4:
    • A six-week-old murdered infant, noted to have three lesions with oval marks, central sparing with slight ecchymosis and no abrasions¹⁰
    • Arch size and slightly oval bite pattern are consistent with a child’s dentition; absent permanent teeth and deciduous molars indicated it was caused by child aged 2 ½ – 6 years¹⁰
    • A four and a half year old child was identified as the perpetrator out of 37 possible contacts¹⁰
    • In the absence of the bite, the child would not have been considered as a possible perpetrator¹⁰

• • Case 5:
    • A teenage girl was assaulted and bitten on her hand¹¹
    • Distinguishing features of the bite: two arcs joined at a diffuse larger mark; one fairly continuous lesion with four separate components – two circular marks, two elongated next to each other. The elongated marks were caused by upper central incisors, the circular marks were caused by canines¹¹
    • The intercanine distance of 23mm suggests abnormal teeth, thus enabling identification of the suspect¹¹
    • This case was the first report of a bite on a child assisting forensic identification¹¹

1.1. Features which suggest that a skin lesion on a child is a bite ^7-11

• • An annular appearance of the lesion made by two opposing concave arcs
  • Irregularities within the arc secondary to individual tooth characteristics
  • A central ecchymotic area within the bite mark can occur
  • Individual characteristics within the bite mark can be further analysed by forensic dentists to assist in identifying or excluding perpetrators

1.2. Implications for practice

• • A human bite on a child should be suspected if there is any 2-5cm oval / circular injury, with a circumscribed annular border, with or without central ecchymosis
  • Any suspicious lesion must have photographs taken with a right-angled measuring device and these need to be taken in each plane if the injury is on a curved surface
  • Early referral of suspicious injuries to forensic dentists is mandatory to enable possible identification of a specific perpetrator

1.3. Research implications

Further research is needed in the following areas:

• • To confirm standard intercanine measurements used clinically
  • To valdidate the characteristics described in international guidelines in a large-scale study

1.4. Limitations of review findings

• • Poor quality evidence
  • No case-control studies
  • Small numbers of children
  • Lack of any confirmation of standard diagnostic criteria for diagnosis of bites
  • Several studies describing large numbers of children with bites did not meet our inclusion criteria since there were no details as to confirmation that the injury was a bite

The review identified a number of interesting findings that were outside of the inclusion criteria. These are as follows:

Clinical question 1

• Measurement of intercanine distance to distinguish child and adult bites:
  • Less than 2.5 cm: child (deciduous teeth)¹²
  • 5 – 3.0 cm: child or small adult¹²
  • 5 – 4.5 cm: human¹²
  • Greater than 3.0cm: adult¹²
  • However, there is considerable racial, sexual and individual variation¹³
  • Adult dentition reached at 12 years¹³
• Features of carnivorous animal bites:
  • Variable size¹⁴
  • Puncture wounds spaced in relation to canines¹⁴
  • Tear rather than compress flesh¹⁴
• Gender:
  • Boys and girls under 10 years old were equally likely to suffer abusive bites¹⁵
• Retaliation:
  • Three children bit their attackers¹⁵
• Location:
  • The commonest sites for abusive bites were arms (29%), legs (19%), shoulder (10%), back (8.5%), buttocks and face equal (7%)¹⁵
• Tracing perpetrators:
  • An integrated technique increases the likelihood of identifying the perpetrator of a bite¹⁶

No additional material published arising from the bites review.

We performed an all-language literature search of original articles, their references and conference abstracts published since 1950. The initial search strategy was developed across OVID Medline databases using keywords and Medical Subject Headings (MeSH headings) and was modified appropriately to search the remaining bibliographic databases. The search sensitivity was augmented by the use of a range of supplementary ‘snowballing’ techniques including consultation with subject experts and relevant organisations, and hand searching selected websites, non-indexed journals and the references of all full-text articles.

Standardised data extraction and critical appraisal forms were based on criteria defined by the National Health Service’s Centre for Reviews and Dissemination¹⁷. We also used a selection of systematic review advisory articles to develop our critical appraisal forms^18-22. Articles were independently reviewed by two reviewers. A third review was undertaken to resolve disagreement between the initial reviewers when determining either the evidence type of the article or whether the study met the inclusion criteria. Decisions related to inclusion and exclusion criteria were guided by Cardiff Child Protection Systematic Reviews, who laid out the basic parameters for selecting the studies.

Our panel of reviewers included paediatricians, paediatric dentists, designated and named doctors and specialist nurses in child protection. All reviewers underwent standardised critical appraisal training, based on the CRD critical appraisal standards¹⁸, and this was supported by a dedicated electronic critical appraisal module.

Inclusion criteria

General criteria

Ranking of abuse

Distinguishing abuse from non-abuse is central to our review questions. As our reviews span more than 40 years, standards for defining abuse have changed markedly. We have devised the following ranking score where “1” indicates the highest level of confidence that abuse has taken place. These rankings are used throughout our systematic reviews (where appropriate).

Ranking of accident

Ranking of evidence by study type

Definition of levels of evidence and grading practice recommendations

Search strategy

The below table presents the search terms used in the 2014 Medline database search for bites, truncation and wildcard characters were adapted to the different databases where necessary.

Fifteen databases were searched together with hand searching of particular journals and websites. A complete list of the resources searched can be found below.

Pre-review screening and critical appraisal

Papers found in the database and hand searches underwent three rounds of screening before they were included in this update. The first round was a title screen where papers that obviously did not meet the inclusion criteria were excluded. The second was an abstract screen where papers that did not meet the inclusion criteria based on the information provided in the abstract were excluded. In this round the pre-review screening form was completed for each paper. These first two stages were carried out by clinical experts. Finally a full text screen with a critical appraisal was carried out by members of the clinical expert sub-committee. Critical appraisal forms were completed for each of the papers reviewed at this stage. Examples of the pre-review screening and critical appraisal forms used in previous reviews are available on request (clinical.standards@rcpch.ac.uk).