Bruises result from injuries to muscles and body tissues

What is a bruise?

Bruises are a form of mild internal bleeding. They are caused by the release of small amounts of blood into the soft tissues of the body, specifically the connective tissue (under the skin) and muscles. They usually result from minor injuries such as:

Tissue injured in these circumstances causes blood to leak from damaged capillaries, and occasionally, small veins called venules. Blood seeps into surrounding tissue, dispersing into the connective tissue just under the skin.

Blood lying close to the surface may become visible through the skin. Initially, bruises will have a purplish colour but with time, and as the collected blood is removed from body tissue by the immune system, the discolouration changes to yellow or green and finally disappears.

Bruises may appear as swellings

More severe damage to body tissue may be accompanied by a greater degree of bleeding. This may lead to a more discrete collection of blood, discernable as a swelling in the body tissues – either just under the skin or in muscles. This is called a haematoma.

Serious injuries can lead to more extensive loss of blood or internal bleeding – examples of this are seen in accidents such as falling from a height, severe falls from a bicycle or with the involvement of similar forces. These injuries of course, should be attended urgently by a doctor.

How to treat a bruise

Most bruises are mild, painless and do not require treatment as they will disappear and resolve spontaneously.

However, some injuries can give rise to bruises which cause pain and discomfort. Examples of these are:

  • Sprains (as with a sprained ankle or twisted knee)
  • Muscle strains (eg. a sporting injury)
  • Trauma following a fall

In these circumstances, treatment as soon as possible following the injury will prevent more extensive bruising, helping the resolution of the injury as well as the bruise. Steps you can take to help yourself are as follows:

  • Rest the affected area as soon as possible. This is especially relevant with muscle strains or sporting injuries
  • Apply a cold compress. If you don’t have the right equipment, a simple way is to place a packet of frozen peas to the injured area
  • Elevate the damaged part of the body if this is possible

When you should go to your doctor with a bruise

The vast majority of bruises are harmless and the result of carelessness, silly injuries or unfortunate accidents.

There are, however, a number of situations where bruises can be an indication of a more serious medical condition. See a doctor if you:

  • Suddenly bruise easily
  • Are bruising more extensively without an obvious reason
  • See a bruise around your belly button – this could be a sign of acute pancreatitis

Unexplained bruises or bruising easily can be the result of a platelet or blood coagulation problem or other serious health condition.