24.OCT.2019 4 MIN READ | 4 MIN READ

Everyone gets bruises, but how many of us actually know what a bruise is? Here’s our guide to all things black and blue.

What is a bruise?

A bruise, also known as a contusion or ecchymosis, is an injury that results in the purple, black or blue discolouration on the surface of the skin covering the injured area. When your skin gets cut, bumped, or experiences a trauma of some sort, blood vessels known as capillaries burst, and blood gets trapped under the upper layers of your skin causing the discolouration.

Bruises usually change colour over time. Fresh trauma may appear red at first, before turning blue or black due to low oxygen levels at the site. Over time the bruise will turn green and then yellow as the injury heals and haemoglobin from blood starts to break down. Usually bruises will fade away gradually.

Bruises can be categorised depending on your body’s location:

  • Subcutaneous bruises occur under your skin
  • Periosteal bruises occur on your bones
  • Intramuscular bruises occur around your muscles

What causes a bruise?

Causes of bruises
Bruises can appear for many reasons.

The common causes are:

  • Bumping into hard object
  • Sports injuries such as sprains or broken bones
  • Muscle strains that cause microscopic tears under your skin, especially if you exercise a lot

Some people are more likely to bruise than others:

  • Elderly people have thinner, more fragile skin, which is more prone to bruising.
  • People with thrombocytopenia have a low platelet count. Platelets are an important part of the blood clotting process, so sufferers bleed and bruise easily.
  • Those with haemophilia, a genetic disorder that causes excessive bleeding and bruising.
  • Those with Von Willebrand disease, a deficiency that also affects the clotting process and causes bruising more easily.
  • Those with deep vein thrombosis (DVT). Blood clots that form inside a vein may present as a bruise.
  • Patients suffering from cancers such as leukaemia can bruise more easily.
  • People who take aspirin and other medications that thin the blood are more likely to bruise.
  • Those with a vitamin C deficiency will experience slower recovery of their bruises.
  • People with sun damage may have more fragile skin that’s prone to bruising.

Caring for a bruise

Because a bruise occurs beneath the skin, there is usually no risk of infection. Most bruises will heal on their own within a few days.

If your bruise is particularly painful, you could:

  • Apply ice wrapped in a cloth to the affected area to reduce swelling and soothe the pain
  • Rest the injured area
  • Elevate the injured area
  • Take a painkiller like paracetamol. Ibuprofen can cause increased bleeding
  • Apply a natural arnica cream
  • Wear clothing that covers and protects the bruise
  • Be extra careful to avoid aggravating the injury

When to seek help

When to seek help
Depending on the cause of the bruise or the severity, you might need to go to the emergency department.

If the following apply, go to your nearest A&E department:

  • The bruise is as a result of a serious fall or blow
  • Your bruise is accompanied by a heavily bleeding wound
  • The bruise is due to a head injury, as you might have a concussion
  • You have blood in your stool, urine, or eyes
  • You have deep black bruises on your legs, which might indicate DVT

You should also visit your doctor if:

  • You have frequent bruising that doesn’t go away
  • Your bruising is accompanied by bleeding from your nose or gums
  • You have bruises under your nails
  • You have bruises in a recurring pattern across your body
  • You regularly bruise for no reason
  • Your bruise is showing signs of infection, like red streaks, or you have a fever
  • You find the area painful to move even after a few days

Medical Conditions Where Bruising is a Symptom


When a bruise doesn’t heal, grows in size, or feels firm to the touch, it could be a haematoma. A haematoma occurs when blood collects under the skin and forms a lump. The blood has nowhere to go and cannot be released, so it doesn’t heal. If you think you have a haematoma, see a doctor. They can drain the blood from the site to help it heal.

Liver disease

People who drink alcohol excessively may find they bruise a lot, but it’s not always down to tripping over while tipsy. Your liver plays a part in the clotting process, so if you drink heavily and you’ve damaged your liver, you might bruise more easily. A disease known as cirrhosis could be the cause, and it’s a serious illness that needs medical attention. If you drink a lot and you notice regular bruising, see your doctor.

The Bottom Line

In most cases, bruises are nothing to worry about. Everyone gets them, and they don’t usually need medical intervention. However, do seek medical attention if you notice that your bruises or frequency of bruising is out of the ordinary.


Article reviewed by Dr Samuel Low, Clinical Director at Parkway Hospitals


Felson, S. (2019, Apr 29) What Helps A Bruise Heal? Retrieved 26/7/19 from https://www.webmd.com/first-aid/helping-bruise-heal#2

Felson, S. (2018, Aug 7) Why Do I Bruise So Easily? Retrieved 26/7/19 from https://www.webmd.com/skin-problems-and-treatments/why-do-i-bruise-so-easily#2

Jaliman, D. (2017, Nov 18) Bruises. Retrieved 26/7/19 from https://www.webmd.com/skin-problems-and-treatments/guide/bruises-article#3

Taylor, S. (2017, Feb 1) The Colorful Stages of Bruises: What’s Going on in There? Retrieved 26/7/19 from https://www.healthline.com/health/bruise-colors

Weatherspoon, D. (2017, Jul 24) What’s Causing These Black and Blue Marks? Retrieved 26/7/19 from https://www.healthline.com/health/bruise

Dr Samuel Low
Clinical Director
IHH Healthcare Singapore

Dr Samuel Low holds a medical degree and has clinical experience in anaesthesiology/intensive care, primary care and emergency medicine.