Childhood bruising distribution observed from eight mechanisms of unintentional injury.

Objective: To inform the assessment of described mechanisms of bruising in children.

Design: Prospective cross-sectional study.

Setting: The emergency department, and children in the local community.

Patients: Children aged 0-13 years with bruises from unintentional injuries.

Exclusions: bleeding disorder, medication affecting coagulation or child protection concerns.

Interventions: Injury incidents were categorised into one of eight causal mechanisms (fall from<1 m, 1-2 m, fall from standing height or less and hitting an object during fall, stairs or impact, crush, sports or motor vehicle collision).

Main Outcome Measures: Location, number and mechanism of bruising for each injury mechanism.

Results: 372 children had 559 injury incidents, resulting in 693 bruises; 85.2% of children were walking independently, with impact injuries and fall from standing height (including hitting an object) being the predominant mechanisms. A was observed in 81.7% of all incidents. Stair falls resulted in ≥3 bruises only with falls involving ≥10 steps (6/16). Bruising was rarely observed on the buttocks, upper arm, back of legs or feet. in this dataset on ears, neck or genitalia. was only noted in 1/293 unintentional incidents, involving a high-impact injury in a school-aged child.

Conclusion: These findings have the potential to aid an assessment of the plausibility of the explanation given for a child with bruising. Certain bruise distributions were rarely observed, namely multiple bruises from a single mechanism, petechiae and bruising to the ears, neck or genitalia.