The bumps and bruises that show up after an injury can sometimes appear alarming. Pain, swelling, and discoloration are normal reactions to tissue injuries and are often the first sign of the body’s remarkable healing process. Determining the severity of a bruise can be a challenge as an individual’s skin tone and predisposition to bruising vary widely. Here are some basic ways to judge a bruise injury.
Why do we bruise?
Bruises without associated cuts are most often the result of a blunt injury (an injury caused by a forceful impact) to the skin. Blunt injuries can involve a direct impact to the affected area, or a fall onto or against a hard surface. When this happens, softer tissues like skin, blood vessels, nerves, and muscles can temporarily crush against another surface or against the underlying hard bones or cartilage. The crushing breaks tiny blood vessels (capillaries) causing them to leak and creates the recognizable purple/red of a new bruise. You may hear medical terms for bruises as contusions or ecchymosis.
What bruising circumstances need immediate medical care?
- Bleeding tendencies: If you are taking blood thinners (including warfarin or aspirin), you should ask your medical provider about whether the injury needs evaluation. Blood thinners can cause excessive blood loss under the skin where the bruise is forming and cause more severe injury to the overlying skin or underlying soft tissues. Do not stop taking your blood thinner if you develop a bad bruise. Instead, contact your provider for advice. Likewise, if you have a known bleeding/clotting disorder, you are more likely to need medical care for these reasons.
- Legal cases: If a bruise is the result of an assault or abuse, having the bruise medically evaluated will not only ensure that it heals properly, but medical evaluation also creates a record of the injury that may be needed if there are any legal actions in the future.
- Accompanying injuries: If a bruise is obviously associated with other worrisome injuries, such as lacerations or broken bones, seek immediate medical care. This includes bruises around the eye, especially if there is any difficulty moving the eye or seeing.
Severity of a bruise
Certain common areas for bruising (like the thigh) have led clinicians to develop a scale for accessing contusion severity:
- First Degree: Mild pain, no severe swelling, minimal visible bruising; mild tenderness of the area with direct pressure.
- Second Degree: Moderate pain and little swelling; the muscle becomes more difficult to flex; pressure on the area results in definite pain.
- Third Degree: Severe pain and tenderness, noticeable swelling with an obvious bruise; significant loss of motion in the muscle beneath the area of bruising; the bruise and the surrounding area are painful to touch.
What to expect if you have a bruise
Swelling from a bruise can gradually worsen. Bruising can be at its worst about one day after the injury and then will slowly begin to improve. Appropriate treatment within the first two days after bruising may help with associated swelling, stiffness, and pain. The appearance of the bruise also gradually changes; from a dark blue or purple on day two or three, to green or yellow on days five through ten. After day ten or fourteen, the bruise usually further fades to light brown. Most bruises resolve completely within two weeks.
Signs of complications from a bruise include:
- Unusual appearance: If the bruise looks much worse than what would be expected from the way the bruise happened, this may be a sign of more serious injury or an underlying bleeding/clotting disorder that requires medical evaluation. Severe complications of a deep bruise can include compression of blood flow past the injury, causing the limb to appear pale and cool. These cases are rare, but they always require immediate medical treatment.
- Unusual pain or numbness: If the bruise feels much more painful than what would be expected from the way the bruise happened, if you have a loss of sensation, or if you are unable to move the affected body part, this may be a sign of more serious underlying injury.
- Swelling: If the bruise continues to swell 1-2 days after the injury, it could be a sign of a growing hematoma (collection of blood in the soft tissue). This is more common in thigh contusions and may need surgery to remove the hematoma.
The best treatments for uncomplicated bruises include:
- Applying cold compresses. Cold compresses can be bought from a store or pharmacy or made at home with a bag of frozen vegetables wrapped in a towel. Cold compresses can be applied to the affected area(s) 1-2 days after an injury for up to fifteen minutes at a time throughout the day.
- Resting the injured area. Moderate activity should be maintained (like walking), but you should pay attention to your body’s limitations. If a certain movement causes or worsens pain, you should temporarily avoid that movement.
- Elevating the extremity. If you have a bruise on your arm or leg, keeping it elevated may help reduce swelling
As in many other forms of injury, the ultimate treatment is prevention. If you live with someone prone to falls or accidents, such as young children or the elderly, you may take steps to eliminate hazards in the environment. Some examples include installing handrails or rearranging rugs or furniture. If you are participating in an activity at high risk for bruising like playing sports or riding a bike, remember to wear a helmet and other protective gear.
Children’s Hospital of Chicago, “Muscle Contusion (Bruise).”
Cleveland Clinic, “Thigh Contusion.”
Nemours Kids Health, “Bruises,” August 2018.
Philip Buttaravoli, “Contusion: (Bruise),” in Minor Emergencies (Second Edition), (Mosby, 2007), 557-560.
Scripps, “Bewildered by Bruises?,” January 29, 2020.
West Virginia University Medicine, “Bruises: Types and treatments,” May 2017.