Bruises are one of the most common, and fortunately, least serious injuries that many of us experience. A bruise, which in medical jargon is known as a contusion, occurs when a blunt impact damages the tiny blood vessels beneath the skin. Various substances in blood are responsible for the color changes that bruises typically undergo.Immediately following an injury, hemoglobin in the red blood cells is responsible for the reddish color. As the blood beneath the skin breaks down, the characteristic “black and blue” discoloration develops. Later, when special cells, known as macrophages “clean up” the dead red blood cells, the bruise turns to a golden-brown color. Usually, these color changes occur over a 2 to 3 week period while the contusion is healing.
Why do some people bruise more than others? With aging, loss of the layer of subcutaneous (beneath the skin) fat that provides cushioning, as well as increased fragility of small blood vessels contributes to easy bruisability. Medications that interfere with the body’s blood clotting mechanism can also affect how easily bruising occurs. These medications include the commonly taken non-steroidal anti-inflammatory drugs (ibuprofen, naproxen, etc.) as well as aspirin. Corticosteroid medication such as prednisone can promote bruising by causing the small blood vessels beneath the skin to become more fragile. “Blood thinners” (e.g. wafarin or Coumadin), often prescribed to prevent worsening of blood clots in the lower legs, can cause particularly severe bruising. Other causes for excessive bruising include inherited clotting disorders (e.g. hemophilia), certain of the autoimmune diseases (e.g. idiopathic thrombocytopenic purpura), and liver disease, such as cirrhosis.
What causes the lump under the skin? Bleeding beneath the skin is responsible for the initial lump that often occurs following an injury. A pool of blood under the skin that becomes walled off after an injury is known as a hematoma. While technically, a hematoma is a “blood clot”, this type of blood clot is generally less serious than other types of blood clots. For example, a blood clot in the veins of the lower leg (deep venous thrombosis), can “break loose” and travel to the lungs, causing a pulmonary embolus. Injury-related hematomas, on the other hand, are usually reabsorbed by the body without causing serious consequences.
What is the initial treatment for a contusion? The RICE protocol—rest, ice, compression and elevation—-is the appropriate initial treatment for most contusions. With prompt attention, the amount of bruising or hematoma formation can be reduced. The first thing to do is to apply a cold pack. Commercial ice packs, ice placed in a plastic bag, or a bag of frozen peas all work well to provide the cooling necessary to reduce blood flow and limit bleeding beneath the skin. Be careful, however, to not apply the ice pack too tightly or for too long to avoid causing frostbite. A general rule of thumb is to apply the ice pack for 15-20 minutes out of each hour for the first few hours following the injury. Pressure from your hand or with a loosely wrapped elastic bandage provides enough compression to reduce bleeding beneath the skin. If possible, elevate the injured area above the level of the heart, again to reduce blood flow and limit bleeding. Stop taking any non-essential medications, such as aspirin or ibuprofen that could contribute to further bleeding.
When should a doctor be consulted because of bruising? Several situations involving contusions warrant medical attention. These include:
- Bruising, particularly if large or associated with hematoma formation in someone who is taking “blood thinners”. This could be a sign that the level of the blood thinner has become too high.
- Bruising that seems out of proportion to the amount of injury sustained.
- Bruising occurring spontaneously, particularly on areas of the body such as the back, abdomen or chest where injury is unlikely to occur.
- Bruising that develops in association with a febrile illness. Serious infections including meningococcal meningitis and Rocky Mountain Spotted Fever can be associated with bleeding beneath the skin and bruising.
- Bruises that fail to fade away after a 2-3 weeks.
Injury-related bruising is an expected outcome of blunt trauma and is likely to affect us all. By applying the measures discussed above, the severity and extent of the bruise can be limited.
Kent Davidson MD – Health Tip Content Editor
Reviewed and Approved by Charles W. Smith MD, Medical Director on July 29, 2009.