Bruises and haematomas: recognising them, and why colour cannot date them
- Finding
A bruise is blood escaped from broken vessels under intact skin; its colour cannot tell reliably when it happened.
What it is
A bruise (contusion, equimosis) is blood leaking from small vessels broken by an impact into the tissues, with the skin intact. When the blood collects into a palpable mass it is a haematoma. It is the typical mark of a blunt object and can reproduce its shape. Two key ideas for exams and practice: a bruise may appear late or away from the point of impact, and its colour cannot date it reliably. A systematic review concluded that estimating the age of a bruise from its colour has no scientific basis.
How to tell it apart
- Versus livor mortis: on incision a bruise shows blood infiltrated into the tissues; livor stays inside the vessels.
- Versus mimics: congenital pigmented patches, clotting disorders, vasculitis.
- Versus an abrasion: in a bruise the epidermis is intact.
- No bruise at the site of the blow does not contradict the account: it may appear later or elsewhere.
How to recognise it
- A red, purple, green or yellow patch under intact skin that does not blanch on pressure.
- Haematoma: palpable swelling from the collection of blood.
- Patterned bruises: round fingertip marks, two parallel lines from a cylindrical object, the arcs of a bite.
- Bruising at a distance: periorbital with a skull-base fracture, or in lower areas as blood tracks down.
How it forms
- An impact breaks small vessels and blood infiltrates the dermis, the subcutaneous tissue or deeper planes.
- Size depends on force, the tissue (loose versus firm) and the person's clotting.
- Over days haemoglobin breaks down and the colour changes, but at very different rates between people and injuries.
Step by step
- Locate, measure and describe each bruise separately: shape, colour and pattern.
- Photograph with a scale; if possible, repeat the photographs on the following days.
- Record the colours seen without giving them a date.
- Examine fully if there is a suspicious pattern or injury to the neck, chest or abdomen.
- If the first exam shows no bruise and the event was recent, re-examine the next day.
Next step: what to do and document
- Describe and photograph; do not write that a bruise "is X days old" from its colour.
- With bruising of the face, neck, chest or abdomen after a blow, rule out internal injury and do not discharge in a hurry.
- In children, older adults or victims of violence, compare the pattern with the account, start the protection pathway and make the mandatory notifications.
- Arrange a repeat exam if injuries may not yet be visible, and also record when no bruise is seen.
Common mistakes
- Dating a bruise by its colour in a medico-legal report.
- Concluding there was no blow because no bruise is seen at the first visit.
- Attributing a congenital patch or a clotting disorder to abuse without investigating it.
- Writing "multiple bruises" instead of describing each one.
Test yourself
Think of the answer, then tap the question to see it.
Can the age of a bruise be estimated accurately from its colour?
No. A systematic review (Maguire 2005) concluded that ageing bruises by colour has no scientific basis: any colour appears in both recent and old bruises.
Why may no bruise be visible at the site of a blow?
Because it can take hours to appear, track to another area along tissue planes, or be hard to see on dark skin.
What do two parallel lines of bruising separated by normal skin suggest?
A blow with a cylindrical or rod-like object (a "tramline" bruise).
How is a bruise told from livor mortis on incision?
In a bruise the blood has infiltrated the tissues; in livor the blood is inside the vessels and washes away.
Elsewhere in DurgiPedia
- Mandatory reporting: public health, violence and abuse
- Hemorrhage: petechiae, purpura, ecchymosis, hematoma, and what blood loss does
Connections
Educational content on forensic and legal medicine; not legal advice and no substitute for the technical guides of Colombia's National Institute of Legal Medicine and Forensic Sciences. Laws change: each page links the official text and says when it was last checked. For a real case, follow the guide in force and ask the competent authority.
Sources: Can you age bruises accurately in children? A systematic review (Maguire S, Mann MK, Sibert J, Kemp A) (Archives of Disease in Childhood (PMC), 2005); Trauma Forensics in Blunt and Sharp Force Injuries (Journal of the West African College of Surgeons (PMC), 2022); Blunt Force Trauma (StatPearls) (NCBI Bookshelf, StatPearls Publishing, 2023).
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Representative model, for educational purposes only.