An unexplained, mysterious bruise that can’t be tied back to a fall or other injury might make your brain race: Is this cancer?
Bruising occurs when blood collects under the skin after the delicate vessels that circulate blood are damaged or broken, explains Eunice Wang, MD, a hematologist and Chief of the Leukemia/Benign Hematology Service at Roswell Park Comprehensive Cancer Center. A bruise is typically flat and will appear reddish or bluish in color at first — red if the blood is oxygenated and coming from the lungs, blue if it is transporting carbon dioxide back to the lungs to be exhaled — but will change color to yellow, brown or purple as those cells die off and are absorbed back into the body.
Any trauma that is strong enough to break the blood vessels but not enough to break the skin can result in a bruise, but taking blood thinners or too much aspirin can also cause bruising, Dr. Wang says. Sometimes bruising is caused by an imbalance in the body’s bleeding/clotting system due to too many, or not enough, platelets in the bloodstream. Platelets, like red and white blood cells, are formed in the bone marrow and are important in making blood clot. Too many platelets can cause blood clots, which can result in heart attack, stroke and other problems. Too few platelets and people might bleed excessively when injured, Dr. Wang says.
But bruising, or excessive platelets, might also be an indication that your blood cells are carrying leukemia cells as well, which can grow in the bone marrow alongside healthy cells. These bruises are different from the ones we’re used to seeing: they might be much darker red or purple and could be irregularly shaped. Bruises that could indicate cancer might also appear on parts of the body where bruises wouldn’t normally occur, like on the head, face, thighs or back, Dr. Wang says. They will last longer and could appear to spread or multiply or, in the case of a condition called petechiae, it could look like tiny red freckles coupled with small bruises
