Bruising

Bruising, also called a contusion, is a common skin lesion that occurs after blunt trauma. It results from small blood vessels (capillaries) breaking beneath the skin, causing blood to leak into surrounding tissues. The visible discoloration, or ecchymosis, is due to the accumulation and breakdown of blood components. Most bruises heal without treatment.

Mechanism and color changes: Initial bleeding beneath the skin produces a red or dark patch. Over the next days, the bruise often becomes blue to purple as oxygenated blood is degraded. As hemoglobin is broken down, colors shift to green (biliverdin), then yellow or brown (bilirubin and hemosiderin). The body gradually reabsorbs the blood, and the bruise fades in about one to three weeks, depending on size and location.

Causes and risk factors: Most bruises result from minor blunt trauma. Bruising is more common with aging skin, in people taking anticoagulants or with clotting disorders, or with liver disease or certain vitamin deficiencies. Very frequent or spontaneous bruising may warrant medical evaluation to rule out underlying conditions.

Diagnosis and management: Diagnosis is usually clinical. First aid includes rest, ice for 24 to 48 hours, compression, and elevation to reduce swelling. After the first two days, gentle heat can help. Pain can be relieved with acetaminophen; avoid or limit NSAIDs if bleeding risk is a concern. Seek care for large, painful, rapidly spreading bruises, bruising after minor trauma in children, or bruising with other concerning symptoms.