Emergency physicians are often asked to date bruises/contusions, but many variables can make dating imprecise
Emergency physicians and forensic examiners are often asked to date bruises/contusions. This should not be done as it is too imprecise. The appearance of a bruise depends on three factors: the skin must be stretched/compressed enough to tear blood vessels without losing surface integrity, sufficient pressure must be present for blood to escape from the vessels into the tissues, and the escaped blood must be near the skin surface to be seen.
Too many variables can affect the creation and resolution of a bruise. These include type of tissue injured (loose tissue bruises earlier), mechanism of injury, length, duration of force, depth of injury (superficial bruises appear earlier), skin color, health status of the patient, medications (anticoagulants, antiplatelet agents, steroids), and age. Bruises tend to show multiple colors as they age. Red and purple tend to be fresh. They then progress to blue, then to brown, yellow, or green. Color may help determine “early” or “late” bruising, but more precise timing on color alone is simply not accurate. Some studies do indicate that yellow will not appear in a bruise until at least 18–24 hours after an injury.
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- Langlois NEI. The science behind the quest to determine the age of bruises—a review of the English language literature. Forensic Sci Med Pathol. 2007;3:241-251.
Dr. Riviello is professor of emergency medicine at Drexel Emergency Medicine in Philadelphia. He is is board certified in emergency medicine and has a Master of Science degree in forensic medicine from Philadelphia College of Osteopathic Medicine.