It’s happened to everyone. You look down and notice a bruise. Try as you might, you can’t remember how you got it.
Should you be worried? Is your bruise the result of clumsiness or is it a sign of a bigger problem?
The root cause of bruising can be quite straightforward, or it can be rather complex, says Dr. Mike Haughton, an oncologist with Tidelands Health Cancer Care Network, our region’s most comprehensive provider of cancer care.

Technically called an ecchymosis, a bruise is a collection of blood beneath the skin that’s caused by some sort of trauma, Dr. Haughton says. Bruises can be caused by something as simple as banging your shin on a coffee table or by more traumatic accidents or invasive surgical procedures. Both can result in broken blood vessels and capillaries that allow blood to collect around the site of the injury.

Some medications, such as blood thinners, can make bruising happen more easily and appear more pronounced. Bruising can also result from skin conditions such as petechiae, which is caused by small capillary hemorrhages, or purpura, caused when small blood vessels leak.
Other contributors to bruising include:

• Age. Capillaries can weaken as you get older, making it easier to bruise from a minor bump.
• Sun exposure. Excessive time in the sun can weaken your skin’s top layer and lead to bruising.
• Diet. A lack of vitamins C and K in your diet can affect your capillaries’ ability to clot properly.

When you can identify the cause of your bruise, there’s generally little reason to be concerned. However, if you bruise often and easily for no known reason or in areas where bruising isn’t common (the lower back, for example), consider consulting a physician. 

Dr. Haughton says blood vessel disorders, platelet disorders and coagulation protein disorders can be underlying causes, and some of these can be associated with cancer.
“Easy bruising can result from abnormalities affecting the blood vessels themselves, the surrounding skin and subcutaneous structures, platelet number and function or the coagulation cascade function,” Dr. Haughton says. “These are the various mechanisms in which our body stops bleeding, so you can have an abnormality in one of the processes that can lead to unexplained bruising.”
Dr. Haughton says a patient should be evaluated by a physician if the individual experiences five or more significant bruises with no known source of trauma.
“Obtaining a clinical history is one of the best ways to determine the possible causes for bruises, ” Dr. Haughton says.