Bruises: Information on This Common Condition (Damaging of Blood Vessels as a Result of a Blow to the Skin) on MedicineNet.com

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Bumps & Bruises
(Contusions & Ecchymoses)

Medical Author: William C. Shiel Jr., MD, FACP, FACR

What is a bruise?

You fall off your bike, bang your shin on the coffee table (that you swore you would move months ago) or run into a wall and wake up with a wallop of a bruise. What is a bruise, and what can you do about it? A bruise (medically referred to as a contusion) is caused when tiny blood vessels are damaged or broken as the result of a blow to the skin (be it bumping against something or hitting yourself with a hammer). The raised area of a bump or bruise results from blood leaking from these injured blood vessels into the tissues as well as from the body's response to the injury. A purplish, flat bruise that occurs when blood leaks out into the top layers of skin is referred to as an ecchymosis.

Why do bruises occur more frequently in some people than in others?

The injury required to produce a bruise varies with age. While it may take quite a bit of force to cause a bruise in a young child, even minor bumps and scrapes may cause extensive bruising or ecchymosis in an elderly person. Blood vessels become more fragile as we age, and bruising may even occur without prior injury in the elderly.

The amount of bruising may also be affected by medications which interfere with blood clotting (and thus cause more bleeding into the skin or tissues). These drugs include many prescription arthritis medications called nonsteroidal antiinflammatories (for example, ibuprofen [Advil, Nuprin] and naproxen [Aleve]) as well as over-the-counter medications, such as aspirin. Warfarin (Coumadin) is often prescribed by doctors specifically to prevent clotting in patients who have had blood clots in their legs or heart. Warfarin can cause particularly severe bruising, especially if the level of the medication becomes too high. Cortisone medications, such as prednisone, promote bruising by increasing the fragility of the tiny blood vessels in the skin. In addition, patients with inherited clotting problems (such as in hemophilia) or acquired clotting problems (such as in patients with liver diseases like cirrhosis), can develop extensive bruising or even life-threatening bleeding.