The bruise then remains visible until the blood is either absorbed by tissues or cleared by immune system action.

Bruises which do not blanch under pressure can involve capillaries at the level of skin, subcutaneous tissue, muscle, or bone.

Trauma sufficient to cause bruising can occur from a wide variety of situations including accidents, falls, and surgeries.

Disease states such as insufficient or malfunctioning platelets, other coagulation deficiencies, or vascular disorders, such as venous blockage associated with severe allergies[9] can lead to the formation of purpura which is not to be confused with trauma-related bruising/contusion.

[10] If the trauma is sufficient to break the skin and allow blood to escape the interstitial tissues, the injury is not a bruise but bleeding, a different variety of hemorrhage.

Sometimes bruises can be serious, leading to other more life-threatening forms of hematoma, such as when associated with serious injuries, including fractures and more severe internal bleeding.

Bruising present around the navel (belly button) with severe abdominal pain suggests acute pancreatitis.

The harm score is determined by the extent and severity of the injuries to the organs and tissues causing the bruising, in turn depending on multiple factors.

Low levels of damaging forces produce small bruises and generally cause the individual to feel minor pain straight away.

Increased distress to tissue causes capillaries to break under the skin, allowing blood to escape and build up.

The damaged capillary endothelium releases endothelin, a hormone that causes narrowing of the blood vessel to minimize bleeding.

As the endothelium is destroyed, the underlying von Willebrand factor is exposed and initiates coagulation, which creates a temporary clot to plug the wound and eventually leads to restoration of normal tissue.

During this time, larger bruises may change color due to the breakdown of hemoglobin from within escaped red blood cells in the extracellular space.

[23] As for most injuries, these techniques should not be applied until at least three days following the initial damage to ensure all internal bleeding has stopped, because although increasing blood flow will allow more healing factors into the area and encourage drainage, if the injury is still bleeding this will allow more blood to seep out of the wound and cause the bruise to become worse.

[24] The word ecchymosis (/ˌɛkɪˈmoʊsɪs/; plural ecchymoses, /ˌɛkɪˈmoʊsiːs/), comes to English from Neo-Latin, based on Greek ἐκχύμωσις, ekchymōsis, from ἐκχυμοῦσθαι, ekchymousthai, 'to extravasate blood', from ἐκ-, ek- (elided to ἐ-, e-) and χυμός, chymos, 'juice'.