Blood poisoning (septicaemia)

This information for teenagers from Great Ormond Street Hospital (GOSH) is about blood poisoning (septicaemia) – a potentially life-threatening infection which is often a result of another infection in the body.

It happens when bacteria from that infection enters the bloodstream and spreads elsewhere.


Our blood contains millions of white blood cells that fight off infections from bacteria and viruses. These cells are very efficient at fighting infection and will usually keep it under control. For example, when a wound becomes infected your white blood cells will destroy the infection and heal the wound. 

Sometimes infections can develop that can’t be controlled by these cells. This might be because the infection is very bad or because the immune system is weak from another illness. When this happens the bacteria causing the infection can enter the bloodstream. Once in the blood, bacteria can be carried to other tissues and organs in your body causing other complications. 

Blood poisoning can develop from a simple wound or burn or as a result of a serious illness. It is most likely to occur in older people or in young children because their immune systems are weaker. Young people are more at risk if they have recently had surgery or already have a weak immune system.


If you have blood poisoning, your immune system will immediately try to fight the infection in your bloodstream. This will bring on a number of sudden symptoms as your body fights the bacteria. 

These might include:

  • high temperature
  • extreme tiredness
  • violent shivering and chills
  • faintness
  • pale and clammy skin
  • rapid and shallow breathing  

Your skin may also develop pinprick bruises (called petechiae) or large purple areas (called purpura), which do not change colour if you roll a glass tumbler over them. This is a common sign of meningococcal septicaemia, a type of blood poisoning caused by the meningococcus bacteria, which can also cause meningitis. 

In severe cases of blood poisoning the proteins and chemicals released in your blood to fight the bacteria can affect the flow of your blood. When the flow of blood is affected it can lower your blood pressure and ultimately cause damage to some of your organs, like your brain or your kidneys. This is called septic shock.


Blood poisoning can be life threatening so, if you have it, you’ll need to be admitted to hospital as soon as possible. You’ll have blood tests to find out what’s causing the infection and maybe some other tests, like x-rays, scans and kidney, liver and heart function tests, to see how badly other parts of your body have been affected.


If blood poisoning is diagnosed early enough, and it hasn’t affected the way your internal organs function, you can treat it at home with a course of antibiotics. 

If you have a severe case of blood poisoning then you’ll stay in hospital and be put on antibiotics intravenously. This is when antibiotics are delivered straight into your bloodstream through a tube in your vein. If possible, the source of infection (eg an infected wound) will also be treated. 

In the most serious cases, medication may also be used to treat low blood pressure. You might also be supported by machines to help your organs function properly. 


There are a few things you can do to prevent the risk of infection:

  • Keep wounds and burns clean and properly dressed.
  • Seek treatment for any mouth infections and boils.
  • Keep up to date with your immunisations. Immunisation can protect people from certain bacteria that can cause septicaemia. In the UK all babies are vaccinated against group C meningococcus and haemophilus as part of their immunisation programme.
  • Eat a healthy diet and exercise regularly to keep your immune system strong. 

When to ask for medical help 

If you have an infected wound, or you think you have any of the symptoms of blood poisoning, it’s important to seek medical help straight away. 

Looking ahead 

If you have blood poisoning and it is diagnosed and treated quickly you should recover fully without any long-term damage. 

In more severe cases, the damage to your organs and body tissue may affect you permanently. 

In the most severe cases of blood poisoning, when treatment is too late to correct any damage done to your body, it can be fatal.

It’s a good idea to know the signs and symptoms of blood poisoning so you can act quickly.

Last review date: 
June 2014