Bruising, or contusions, occur when blood vessels under the skin break due to impact or trauma. As blood leaks out, it forms a darkened area of the skin, which initially appears red or purple.

Over time, as the body breaks down the blood cells, the bruise may change color, turning blue, green, yellow, and eventually fading away. The severity of a bruise can depend on the force of the impact, and deeper tissue bruising may lead to more significant swelling.

Most bruises heal on their own within a few weeks. The body gradually reabsorbs the pooled blood, and the bruise eventually fades. However, the healing time can vary based on the injury's location and the individual's health.

While bruising is typically harmless, large or painful bruises can be signs of more serious injuries, especially if accompanied by difficulty moving or severe pain. If bruising occurs without an obvious cause, a healthcare provider may evaluate it to rule out underlying conditions, such as blood disorders.