Bruises are usually black or blue marks on the skin that appear after a bump or injury.
Blood from damaged blood vessels beneath the skin collects near the surface of the skin resulting in the appearance of bruising.
As well as accidents and bumps, causes of bruises include:
- Bruises can occur in some people who exercise rigorously such as athletes and weightlifters. These bruises result from microscopic tears in blood vessels under the skin.
- Unexplained bruises that occur easily or for no apparent reason may indicate a bleeding disorder, especially if the bruising is accompanied by frequent nosebleeds or bleeding gums.
- Bruises in elderly people frequently occur because their skin has become thinner with age. The tissues that support the underlying blood vessels have become more fragile.
- Initially a fresh bruise may actually be reddish. It will then turn blue or dark purple within a few hours, then yellow or green after a few days as it heals.
- A bruise is commonly tender, and sometimes even painful for the first few days, but the pain usually goes away as the colour fades.
- Because the skin is not broken in a bruise as with a scrape or cut there is no risk of infection.
When to seek medical advice
- If the bruise is accompanied by swelling and extreme pain, especially if you take a blood-thinning medication for a medical condition.
- If bruising occurs easily or for no apparent reason.
- If the bruise is painful and under a toenail or fingernail.
- If a bruise does not improve within two weeks or fails to completely clear after three or four weeks.
- If you think you have a broken bone along with the bruise, go to your nearest hospital's accident and emergency department.
If a bruise shaped like an egg occurs on the head, but the person did not black out and is able to remember the accident, it is unlikely that a serious head injury has resulted. However if the person cannot remember what had happened and you suspect the person may have a concussion, he or she should be taken to the nearest accident and emergency department.
If a bruise occurs just above the eye, you can expect the bruise to travel to the area just under the eye, possibly causing a black eye, because of the effects of gravity. As long as you are able to move the affected eye in all directions and do not have changes in your vision, it is unlikely to be a serious injury that requires a visit to the hospital.
Examinations and tests
If an injury is obviously a bruise and broken bones are not suspected, further tests are unlikely to be carried out.
- If there is swelling or severe pain, an X-ray of the area may be requested to make sure there are no broken bones.
- If bruising occurs frequently and for no apparent reason, blood may be tested to look for a bleeding disorder.
- Certain bruises, a pattern of bruises over time and in various stages of healing may alert a doctor to the possibility of physical abuse.