A bruise is a skin discolouration caused by damage to the underlying small blood vessels. The damage causes a disruption to the flow of blood, with blood accumulating beneath unbroken skin. Bruises take roughly two weeks to disappear and may take a little longer to disappear from the lower legs.1 The colour of the bruise is determined by the breakdown of haemoglobin- the iron-containing component in red blood cells that carries oxygen. When first formed, bruises are red in colour, as the blood is fresh under the skin. Within a day or two, the bruise will turn bluish-purple or black. Within 5-10 days, the bruise may become green or yellow, and by the end of the two weeks, the bruise will finish as yellow or light brown, before fading completely.2
Besides bruises, there are several types of bleeding that can cause similar discolouration of the skin, such as:
- Haematoma- a larger collection of blood outside of the blood vessel, that is typically raised and painful to touch. They can be formed after major trauma
- Petechiae- Pinpoint areas less than 2mm of reddish dots that don’t turn white when gentle pressure is applied
- Purpura- Small bleeding under the skin that is larger than purpura but smaller than bruises3
Possible causes of easy bruising
Bruising is often the result of accidental trauma or a minor injury. If, however, you are finding that you have excessive or unexplained bruises, then it may be due to an underlying condition, which causes you to bleed excessively.
In bleeding, there are three main steps that the body does to attempt to reduce the loss of blood. When a blood vessel is damaged, the body must repair it to stop the escape of blood, in a process called hemostasis. Methods include the accumulation of platelets. Then blood vessels constrict to try and reduce the flow of blood while the vessel is being repaired, and the body releases substances called clotting factors to help the blood come together in a process known as coagulation, Defects in any of these stages can lead to excessive bleeding and bruising.1
Possible causes are,
- Platelet disorders- Autoimmune disorders, leukaemia, or kidney disease can lead to fewer or dysfunctional platelets (called thrombocytopenia)
- Autoimmune disorders- conditions such as lupus and aplastic anaemia can lead to fewer platelets in your body, alongside many other symptoms
- Leukaemia- Leukaemia is cancer of the tissue which forms blood cells, causing an overproduction of defective white blood cells, which are essential to fight against infection. Cells that go on to form platelets come from the bone marrow, meaning that fewer platelets can be produced4
- Kidney disease- patients with advanced kidney disease are prone to bleeding due to loss of elasticity in the skin, alongside an increase of waste products in the blood, and taking medication that can interfere with bleeding5
- Disorders of the blood vessels
- Vasculitis- is the condition of inflammation of the blood vessels. This leads to weaker walls that are more prone to damage
- Vitamin C deficiency- or scurvy, causes a reduction in the formation of collagen, a substance that gives blood vessels their strength, weakening the walls of blood vessels6
- inherited disorders such as Marfan syndrome can lead to defective, weaker blood vessel walls
- Clotting disorders
- Von Willebrand disease- a disorder where an important factor involved blood formation, called von Willebrand factor, is either missing or does not work properly
- Vitamin K deficiency- vitamin k is essential for the formation of clotting factors
- Liver disease- any disorder of the liver can lead to the disruption of the formation of clotting factors
- certain medications can affect any of these three stages of bleeding control. Examples include blood thinners, or alcohol7
Management and treatment for bruise
Bruises can be uncomfortable and unpleasant to look at. There are a few home treatments that help speed up your healing process,
- Elevate the bruised area above heart level if possible
- Apply an ice pack to the bruised area for at least 20 minutes. Repeat several times for a few days after the injury to help reduce the pain and swelling
- If there is swelling, use a compressive bandage, but ensure it is not too tight
- Take over-the-counter pain medication, such as paracetamol or ibuprofen, to help manage the pain8
If medication, such as blood thinners, is the underlying cause for excessive bruising, then your doctor may suggest switching your medication to one with fewer side effects.
How to prevent bruising
Since bruises are most often caused by accidental trauma, trying to eliminate the likelihood of tripping or unnecessarily hard contact is the best way to prevent the formation of bruises. Methods of preventing unnecessary bruises include
- When playing sports, wear protective clothing and equipment, such as shin pads
- Keep objects and furniture out of walk ways
- If you find that you are unsteady when walking, using walking aids may help prevent falls.
- Ensure that your diet has plenty of vitamin C, which can be found in fresh fruit and vegetables
- If on blood-thinning medication, frequently have your blood monitored to ensure that there are no deficiencies in clotting factors
- Ensuring that your living space is free from tripping hazards
- Reducing your intake of alcohol1,3
When should I call a doctor for bruise
Bruises will sometimes require medical attention. You should seek urgent medical advice if you have swelling and extreme pain with a bruise, as this could indicate a possible fracture of the underlying bones. Otherwise, you should seek an assessment from a healthcare provider if you are experiencing any of the following:
- Bruising more frequent and severe than normal
- Unexplained bruising
- Bleeding gums, or bleeding in your urine or stools.
- Painful bruising under the fingernails
- Bruising that lasts for more than two weeks
- A lump in the bruised area
- Painful swelling
- Recurrent bruising in the same area1,3
Bruising is a common sign often caused by accidents and will resolve by itself in due course. Sometimes, however, they can be a sign of an underlying condition, especially if you are finding yourself bruising easily, excessively, and without cause. If you are concerned by a bruise or the frequency of bruising you are experiencing, visit your healthcare provider to seek medical advice and to investigate any concerning symptoms.
- Bleeding and bruising [Internet]. [cited 2023 Jan 24]. Available from: https://dermnetnz.org/topics/bleeding-and-bruising
- Jeney V, Eaton JW, Balla G, Balla J. Natural history of the bruise: formation, elimination, and biological effects of oxidized hemoglobin. Oxid Med Cell Longev. 2013 May 16;2013:703571.
- Bruises (Ecchymosis) [Internet]. Cleveland Clinic. [cited 2023 Feb 12]. Available from: https://my.clevelandclinic.org/health/diseases/15235-bruises
- Bruising in leukaemia VS ordinary bruising [Internet]. Leukaemia Care. 2019 [cited 2023 Feb 12]. Available from: https://www.leukaemiacare.org.uk/support-and-information/latest-from-leukaemia-care/blog/spotting-the-difference-bruising-in-leukaemia-vs-ordinary-bruising/
- Kaw D, Malhotra D. Platelet dysfunction and end-stage renal disease. Semin Dial. 2006 Jul-Aug;19(4):317–22.
- Fraser IM, Dean M. Extensive bruising secondary to vitamin C deficiency. BMJ Case Rep [Internet]. 2009 Feb 26;2009. Available from: http://dx.doi.org/10.1136/bcr.08.2008.0750
- CKS is only available in the UK | NICE. [cited 2023 Jan 24]; Available from: https://www.nice.org.uk/cks-uk-only
- Bruise: First aid [Internet]. Mayo Clinic. 2022 [cited 2023 Jan 24]. Available from: https://www.mayoclinic.org/first-aid/first-aid-bruise/basics/art-20056663