Study note
Forensic MedicineMECHANICAL INJURIES

Bruise healing and the sequence of colour changes

THE CONTEXT
Bruises heal through destruction and removal of extravasated blood. Their colour reflects blood breakdown, but the rate of change varies.

Healing and pigment formation

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Healing is faster in more vascular areas, with smaller contusions and in healthier individuals.
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Red cells disintegrate by haemolysis. Enzymes break haemoglobin down into haemosiderin, haematoidin and bilirubin.

Colour sequence

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Colour change begins at the periphery and progresses inward towards the centre.
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The stated sequence is red initially; blue from a few hours to 3 days; bluish-black to brown on the fourth day, associated with haemosiderin; greenish at 5–6 days, associated with haematoidin; yellow at 7–12 days, associated with bilirubin; and normal colour at 2 weeks.
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These timings are variable, including between bruises in the same person.

Factors affecting observed colour

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The depth and amount of bleeding, environmental lighting and overlying skin colour affect the apparent colour of a contusion.
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