Bruises are a part of life. If you use your body, it's going to get bruised at some point. By the time you notice a bruise, though, it's already started to heal.
A bruise, also called a contusion, is nothing more than bleeding that occurs under your skin or in the soft tissue beneath it, says the Nemours Foundation (NF). The bleeding occurs because trauma to the body has caused blood vessels to break. The blood has nowhere to go and gets trapped under the skin.
Consider a black eye, for instance. It's not a "black" eye at all, but dark purple and green. Those are the colors of the blood and its breakdown products beneath the skin. The skin around your eye tends to be loose and transparent. This allows the color to be seen as a true "shiner."
As a bruise heals, it changes color until it disappears. Bruises typically change color in a progression from a reddish blush to a gradually darkening blue or purple, followed by green and finally yellow-brown.
This color change occurs because white blood cells are removing the decayed blood products little by little, the NF says. Different components of the blood have different colors, and these colors in turn lend color to the bruise. Green, for example, represents a component called biliverdin. Yellow-brown represents bilirubin.
If you have a bruise that's a yellowish color or a yellow-green, it's an old bruise -- probably several days old. The color change begins either at the outside of the bruise or at the center, depending on how the bruise occurred.
The closer the broken blood vessels are to the surface, the sooner the bruise appears and the more intense its colors will be.
Most small bruises disappear within seven days, and larger ones go away within two weeks. Bruises may last longer in elderly adults, however, because restricted circulation slows the removal of the decaying blood components. This may be particularly true in the legs, where circulation may be restricted because of clogged arteries.
Whether a bruise forms depends on the angle and the duration of the impact, as well as the size, shape and weight of the object that hits your body. The most significant factor, however, is the speed of the impact -- faster blows are more likely to create a bruise.
Some people bruise more easily than others. You're more likely to be black-and-blue if you regularly take anticoagulants or aspirin, both of which interfere with clotting. If the blood doesn't clot properly, more of it will leak out under the skin when trauma occurs.
To treat a bruise, the first step is to apply ice, but not for more than 15 minutes at a time. Ice numbs the pain and slows down the bleeding. After two days, you can begin to apply heat. This speeds recovery by increasing circulation in the affected area. If you can, elevate the area that is bruised.
When does a bruise require medical attention?
If you have a bruise, but you don’t recall being hit or injured where the bruise appears.
If the pain is out of proportion to what you might expect from the injury.
If the bruise is larger than what you'd expect from the injury.
If the pain worsens; the pain should lessen with time.
People with a condition called hemophilia (blood disorder) or persons taking anticoagulants (blood thinner) should probably talk to their health care provider if they get a bruise. And if you seem to develop bruises in the course of your normal activities, without a related increase in falls or bumps, also check with your provider.
© 2014 Main Line Health