1.4 Explain what is meant by systemic infection and localised infection

This guide will help you answer 1.4 Explain what is meant by systemic infection and localised infection.

Infection control is a significant part of providing safe health and social care. Knowing the differences between systemic and localised infections helps you recognise the signs early, protect people’s health, and stop the spread of illness. In this guide, we will cover what is meant by both “systemic infection” and “localised infection”, with examples, signs, causes, complications, and the importance of early detection.

What Is an Infection?

An infection happens when harmful microorganisms, such as bacteria, viruses, fungi, or parasites, enter the body and begin to multiply. These germs can cause disease by damaging tissues or producing toxins. Not every microorganism causes infection: some are harmless, and some even help keep us healthy.

When an infection is present, the body’s immune system tries to fight it off. How the infection affects the body depends on its location and how widespread it becomes.

What is Localised Infection?

A localised infection happens when harmful germs are restricted to one specific area of the body. The infection stays at the site where the germs entered or started to grow, and does not usually affect other areas or organs.

Examples of Localised Infection

• Abscess (a collection of pus in the skin or other tissues)
• Infected wound (cut or scrape that has become red, warm, swollen, and full of pus)
• Ear infection (otitis media or otitis externa)
• Boil (furuncle)
• Throat infection (pharyngitis affecting only the throat)

In these cases, the germs have not entered the bloodstream or spread to other organs.

Signs and Symptoms of Localised Infection

Localised infections show clear signs at the affected area. The four main signs are:

• Redness at the site
• Swelling around the area
• Pain or tenderness
• Heat or warmth felt in the infected area

Often, you may see:

• Pus or discharge
• Loss of function in the affected part (for example, trouble moving a finger with an infected cut)
• Localised rash

Usually, the person does not feel unwell throughout their whole body. Sometimes, if the infection is more severe, mild fever or general discomfort may happen, but it is mainly restricted to one place.

Causes of Localised Infection

Localised infections usually start when germs enter the body through a break in the skin or a natural opening. Causes can include:

• Cuts, grazes, or wounds
• Insect bites or animal bites
• Surgical incisions
• Poor hygiene, leading to bacteria on the skin
• Blocked sweat glands or hair follicles

The immune system often contains the germs at the site, preventing their spread.

Possible Complications of Localised Infection

A localised infection can sometimes become worse or spread. If untreated, bacteria might move from the site into the bloodstream, becoming systemic. Recognising the signs early can stop this from happening.

Factors that can increase the risk of complications include:

• Poor immune system (from illness or medication)
• Diabetes
• Older age
• Delayed treatment
• Poor wound care or hygiene

What is Systemic Infection?

A systemic infection happens when harmful germs spread from the original site to other parts of the body. This means the infection affects the whole body, not just one isolated area.

How Does Infection Become Systemic?

Germs can enter the bloodstream through a wound or from another local infection. Once in the blood, they can travel to other organs, bones, or tissues. This can quickly become serious.

Examples of Systemic Infection

• Sepsis (a life-threatening reaction to an infection where the body’s response starts to harm its own organs and tissues)
• Bloodstream infection (sometimes called septicaemia)
• Influenza (the flu virus usually spreads throughout the whole body)
• HIV (a virus that spreads and lives in the blood, affecting the entire immune system)
• Tuberculosis (TB can become systemic when it spreads beyond the lungs to other organs)
• Bacterial meningitis (starts in the blood and infects the brain and spinal cord)

Systemic infections usually cause symptoms away from the original site and affect various parts of the body at once.

Signs and Symptoms of Systemic Infection

Systemic infections often begin with signs that can feel like common illnesses. Common symptoms include:

• Fever
• Chills or sweating
• Rapid heart rate
• Rapid breathing or difficulty breathing
• Fatigue or feeling weak
• Nausea or vomiting
• Loss of appetite
• Confusion or changes in mental state (especially in older adults)
• General aches and pains

As the infection progresses, specific organs can be affected, leading to:

• Low blood pressure
• Organ failure (kidneys, liver, lungs)
• Light-headedness or fainting
• Drowsiness or difficulty waking

Prompt medical help is needed with any signs of a systemic infection.

Causes of Systemic Infection

A systemic infection can begin in several ways. Some causes are:

• Bacteria, viruses, fungi, or parasites entering the bloodstream
• Untreated local infection spreading
• Medical procedures introducing germs to the bloodstream
• Weak immune systems

People with long-term health conditions, recent surgery, or wounds are at higher risk.

Possible Complications of Systemic Infection

Systemic infections can become life-threatening quickly. Sepsis is the most severe form. If not treated quickly, it can lead to:

• Organ damage or failure
• Permanent disability
• Shock
• Death

Recognising early symptoms and quick action can save lives.

Comparing Localised and Systemic Infection

Understanding their differences helps inform your practice. Take note of these key points:

Localised Infection

• Affects one area of the body
• Shows signs at one site (redness, swelling, heat, pain)
• May produce pus
• Person might feel well otherwise
• Less likely to cause widespread symptoms unless untreated

Systemic Infection

• Germs spread throughout the body, often through blood
• Symptoms occur all over (fever, chills, fatigue, confusion)
• Can cause damage to many organs at once
• Is a medical emergency if not treated quickly
• Often starts from a local infection that spreads

Aspect	Localised Infection	Systemic Infection
Location	One area or organ	Whole body or multiple organs
Symptoms	Redness, heat, pain, swelling	Fever, chills, weakness, organ signs
Spread	Does not spread widely	Spreads through bloodstream
Severity	Mild to moderate	Severe, life-threatening possible
Example	Boil, wound infection	Sepsis, flu, HIV

Early Recognition

Spotting a localised infection early gives you the best chance of limiting harm. Treatment can often prevent the infection from spreading. In the case of a systemic infection, quick response is even more important, as delays can have serious consequences.

Health and social care workers must watch for early signs and act. If you notice redness, swelling, or pus in a wound, report it. Watch for flu-like symptoms such as fever, confusion, or rapid breathing, especially if someone is already unwell or has an infection elsewhere.

How Infection Spreads in Care Settings

Both types of infection can have serious effects in health and social care settings. Infection can spread from person to person through:

• Direct contact (touching wounds, helping with personal care)
• Shared objects (towels, bedding)
• Airborne droplets (coughs, sneezes)
• Contaminated surfaces (door handles, medical equipment)

Systemic infections often spread from someone with a wound or respiratory infection, so good hygiene is always necessary.

Practical Steps in Preventing and Managing Infections

Workers play a major role in preventing both localised and systemic infections. You can help by:

• Washing hands regularly with soap and water
• Using disposable gloves and aprons when caring for wounds or unwell people
• Cleaning and dressing wounds properly
• Keeping the environment clean (especially kitchens, bathrooms, all shared spaces)
• Reporting any unexplained illness, fever, or confusion
• Following infection control guidance, including isolation when needed

Clean, prompt first aid for all scratches and wounds can often prevent localised infections turning systemic.

Reporting and Record Keeping

Clear reporting helps stop infection spreading. Record all signs of infection, especially:

• Red skin, swelling, pus, or pain at any site
• Any fevers, chills, or general signs of illness
• Sudden confusion, tiredness, or changes in condition

Share information with your manager or the nurse on duty right away. Good record keeping ensures treatments are given, and patterns get spotted early.

Person-Centred Care in Managing Infections

Each person is different. Age, health, existing conditions, and personal habits play a big part in how an infection affects them. People with weak immune systems, wounds, or recent hospital stays are more likely to develop severe infections.

Show respect and give clear, honest explanations to the people you support. Reassure them about what is happening, the signs you are watching out for, and your actions to help protect them.

Final Thoughts

Your knowledge of localised and systemic infections supports safe working and protects the well-being of people in your care. Always treat new infections quickly, keep good records, and share your concerns. If in doubt, ask a senior colleague or medical professional for guidance. Regular training and awareness protect everyone.

Recognising the differences between infections is a core part of your role in health and social care. Your actions have an impact on outcomes and quality of life for those you support.