Why is easy bruising so common in older adults?

Most bruises form when small blood vessels, called capillaries, near the skin's surface are broken by the impact of a blow or injury. This often happens on the arms or legs. Blood then leaks out of the vessels. At first, the blood looks like a dark mark. Over time the body reabsorbs the blood, and the mark disappears.

Generally, harder blows cause larger bruises. But if you bruise easily, even a small bump may cause a large bruise.

Some people tend to bruise more easily than others. And as people get older, the skin becomes thinner. It also loses some of the protective fatty layer that helps cushion blood vessels from injury.