Last updated: 11.07.23

What is Sepsis and Septicaemia?

What is Sepsis and Septicaemia?

Please Note: If you are in any doubt as to whether someone is suffering from the early stages of sepsis, then you should call NHS 111 and seek professional advice immediately. In cases of severe sepsis, or septic shock, the situation is an emergency and you should go to your local A&E department, or call 999.

Sepsis (sometimes known as a blood infection or septicaemia) is a serious medical condition that arises as a result of infection. In some cases, it can lead to organ failure and is a life-threatening condition, which means understanding the symptoms and causes of sepsis is incredibly important.

If you work in a healthcare setting or work with people that are more at risk of developing sepsis, being able to quickly spot the signs of this condition can help to save lives. In this article, we’re going to look at how it happens, sepsis symptoms, who is at risk, and how sepsis can be treated.

What are Sepsis and Septicaemia?

The words sepsis and septicemia are sometimes confused. Sepsis is the more commonly encountered term which refers to the condition itself. Septicaemia is considered an outdated term by some institutions, and refers more specifically to the bacteria that have caused sepsis.

Sepsis is the term used to describe what happens when the body has a severe immune response to a form of infection, which begins to damage the person’s tissue and organs. The immune system fails to contain the infection to a particular site, and immune responses such as inflammation spread throughout the body, with the potential to cause significant damage. 

Numerous types of infection can trigger sepsis, with common causes of sepsis ranging from urinary tract infections to appendicitis. What can begin as a very mild infection can develop into a serious illness, so understanding what causes sepsis and how to identify it is very important.

What Are the 3 Stages of Sepsis?

The development of sepsis infection is categorised into three different stages.


The initial stage of sepsis is the condition we have explained above, where the immune system cannot contain an infection to a single site in the body and triggers inflammation all over the body as a response. This stage is usually where the first sepsis signs and symptoms start to present themselves, and immediate medical attention is required to get the condition under control.

Severe Sepsis

Severe sepsis develops if the initial stage of sepsis isn’t treated. Inflammation around the body starts to damage the internal organs, leading to more serious and noticeable symptoms that indicate that something is seriously wrong.

A person with severe sepsis may experience damage to their brain, heart, lungs, kidney, liver, or a combination of any of these organs. The affected organ will impact the kind of severe sepsis symptoms that they experience.

Septic Shock

If severe sepsis is left untreated, it can develop into septic shock. This is the most serious kind of sepsis and the hardest to treat, which is why reacting quickly to sepsis signs and symptoms is so important.

Septic shock occurs when a patient’s blood pressure falls as a result of internal damage to their organs. This means that their blood is no longer able to pump all around the body, which can lead to major complications that can make a person even more critically unwell.

Permanent organ damage can be a result of septic shock, as can tissue death, or gangrene, which usually requires amputation to remove the affected area of the body. Whilst a person may recover from septic shock, the damage caused by being in this state may be irreversible and leave them with permanent damage or related health problems.

What are the Signs of Sepsis?

Sepsis has varying symptoms, which may manifest in some patients and not others. In addition, the symptoms of sepsis can vary between age groups, which we’ll explain in more detail in the section.

Symptoms of Sepsis in Children Under 5

In children under five, sepsis can be extremely serious. If you’re in any doubt about the symptoms of a young child, you are recommended to seek further advice from NHS 111.

Initial sepsis symptoms in children under 5 can include the following. 

  • A high temperature of over 38 degrees celsius, or a low one of under 36
  • Difficult or irregular breathing
  • No urination for a long period of time
  • Disinterest in anything, irritability or confusion
  • No drinking for more than 8 hours
  • Particularly green or black vomit, or vomit with blood present
  • Swelling of the soft spot on a baby’s head

The following sepsis signs are more severe – if a child presents any of these, then you should seek emergency medical help immediately by calling 999 or visiting your nearest A&E:

  • Having a fit or seizure
  • Feels particularly cold to the touch
  • Is breathing rapidly
  • Is pale or an unusual or mottled colour, including blue
  • Has a rash that does not whiten upon being pressed

Symptoms of Sepsis in Adults and Older Children

In adults and children over five, the most commonly encountered symptoms of early sepsis include the following:

  • A particularly high or low body temperature
  • Increased heart rate
  • Rapid breathing

Again, you are advised to seek advice from NHS 111 if you or anyone else suspects sepsis as a result of the above signs of sepsis in adults. 

The below blood infection symptoms can be present in more severe cases of sepsis, or even septic shock. If you experience these yourself, or note these sepsis symptoms in adults, then call 999 immediately.

  • Dizziness, feeling faint or even falling unconscious
  • Confusion, disorientation, and slurred speech
  • Vomiting and diarrhoea
  • Severe bodily and muscle pain
  • Lack of urination
  • Mottled, or cold and clammy skin
  • Difficulty breathing or breathlessness

How Long Does Sepsis Take To Develop?

Sepsis is known as a particularly dangerous medical condition because of the speed at which it can develop. There’s no set period of time that it takes for a person to develop sepsis, but once the first signs of sepsis start to appear it can take only twelve hours for them to have died from complications relating to the condition.

The speed at which sepsis develops is worrying, but when it is treated as quickly as possible, patients can often make a full recovery.

Who is Most at Risk?

As with many severe conditions, certain groups are significantly more at risk of sepsis than others. They are also more at risk of developing severe complications. These groups include the following:

  • Those who have a pre-existing medical condition that weakens their immune system, such as HIV
  • Young children
  • Elderly people
  • People in hospital recovering from surgery, with drips or catheters, or on mechanical ventilation
  • People with serious wounds as the result of an accident
  • Pregnant women

How Do You Treat Sepsis?

Sepsis treatment can vary significantly depending on the person’s medical conditions, the seriousness of the sepsis, and which organs have been affected.

In general, the primary course of action will be to stabilise the patient, mitigate the effects of the immune response where possible, and give them a course of antibiotics to destroy the infection itself. These antibiotics will most likely be given intravenously, and may later be given orally as the situation improves. 

If the infection that has triggered the sepsis is viral in nature, antibiotics will have no effect, and other medication will be administered as part of sepsis management.

Severe sepsis and septic shock have a high mortality rate, which means that emergency care is required. Patients will generally be admitted to an intensive care unit (ICU), where they are likely to receive intravenous fluids, oxygen, and potentially other life-supporting measures to keep them alive as they fight off the infection.

Is Sepsis Fatal?

Whilst it’s important to understand that responding quickly to the signs of sepsis is the best way to prevent it from becoming life-threatening, sepsis is a very dangerous condition that sometimes cannot be cured. According to data from The UK Sepsis Trust, around 48,000 people die from sepsis-related illness in the UK every year, so whilst it isn’t a fatal condition for everyone that develops it, many people lose their lives because of it.


What is the most common cause of sepsis?

The most common causes of sepsis are bacterial infections, and the most common places that sepsis develops are the lungs, urinary tract, abdomen and pelvis. These can begin as seemingly quite harmless, which is why some people fail to recognise the early symptoms of sepsis when they begin, as they don’t connect the two together.

What does a sepsis rash look like?

Sepsis can sometimes cause a hemorrhagic rash in people that have it, which can be identified by what looks like a cluster of red, pinprick-like dots on the skin. Over time, this rash might get bigger and start to look more like a bruise.

You can tell whether a rash is caused by sepsis because it won’t disappear when you press down on it. A good way to check for this is to press a glass over the top of the rash, as you’ll be able to see through to check whether it’s disappeared.

How long does it take to recover from sepsis?

Sepsis can take a long time to recover from, but varies from person to person. In some cases, sepsis may trigger what is known as post-sepsis syndrome, which is a long-term condition that can weaken your immune system, make you very tired and lead to negative changes in your mood.


Sepsis is a very serious condition that can affect anyone, developing very rapidly and causing irreversible damage even if the initial infection is treated. Being able to recognise sepsis symptoms and act as quickly as possible gives people with sepsis the best possible chance for survival, and spreading awareness of these symptoms and their severity with articles like this one could help to save lives.

To find out more about the infections that can cause sepsis and how you can prevent them, our clinical ‘Infection Prevention & Control’ online course is part of our Statutory and Mandatory training resource collection and is suitable for anyone working in a healthcare setting.