What Is Inflammation?

Inflammation is the body’s innate process of inducing white blood cells to reduce bodily damage, and  always present to some degree. The immune system controls inflammation to protect us from health threats and promote healing, and this process is constant throughout our lives. Problems can arise if this system becomes uncontrolled and the defence mechanism itself becomes detrimental to health.

Inflammation is a natural defence mechanism and part of the immune system's response to health threats including injury, infection or irritation. This complex biological process involves many cells, chemicals and blood vessels working together to protect the body and promote healing.

Learn here about what inflammation is, the different types of inflammation and what may trigger it. Become aware of the signs of inflammation in your body and how making lifestyle changes, including improving your diet and exercising, can prevent many inflammatory diseases.

Overview

When the body detects tissue damage or an invading pathogen, an immune response is triggered. Chemical signals are released such as cytokines and histamines which attract immune cells to the affected area. These immune cells, including white blood cells, move to the site of infection or tissue damage to fight the harmful substances and initiate the healing processes. 

Blood vessels in the affected area become more permeable which allows immune cells to travel from the bloodstream and into the tissues. Increased blood flow causes symptoms of redness, warmth and swelling, and the release of chemicals causes pain or discomfort. 

Acute inflammation is an important, protective response that the body needs in order to fight infection and heal from tissue damage. Chronic infection can eventually become very harmful to the body if allowed to persist and underlies the development of many common diseases including cardiovascular disease, asthma and some cancers.

Types of inflammation

There are two main types of inflammation, acute inflammation and chronic inflammation. A third, less common, type is sub-acute inflammation.

Acute Inflammation 

Acute inflammation has a rapid onset and can quickly become severe, lasting for several  days. Examples of acute inflammation are cellulitis and acute pneumonia. It is a response to tissue damage and can be caused by any of the following¹:

• Physical trauma
• Microbial attack
• Noxious compounds 

Chronic Inflammation 

Chronic inflammation is slow and long-term, lasting from several months to several years. The severity of chronic inflammation and the extent to which it affects the sufferer will depend on the cause and the systems/organs it affects.

Sub-acute Inflammation 

Sub-acute inflammation marks the period of time between an acute phase of inflammation and the onset of a chronic phase. Typically the sub-acute phase lasts between 2-6 weeks.

Causes of inflammation

The main causes of inflammation are²-

• Pathogens 
• Damaged cells
• Toxins

Non-infectious causes of inflammation

Physical causes: 

• Burns 
• Frostbite
• Physical injury/tissue and cell damage
• Foreign bodies 
• Radiation 

Chemical causes:

• Excess glucose 
• Fatty acids 
• Toxins 
• Alcohol 
• Chemical irritants 

Infectious causes of inflammation 

• Bacteria 
• Viruses 
• Other microorganisms 

Chronic inflammation is caused by DAMPS (damage-associated molecular patterns)³, and acute infections are caused by PAMPS (pathogen-associated molecular patterns).

Signs and symptoms of inflammation

There are five ‘classic’ signs of inflammation⁴:

• Dolor- meaning pain
• Calor- meaning heat 
• Rubor- meaning redness
• Tumor- meaning swelling 
• Functio laesa- meaning loss of function 

Other signs and symptoms of inflammation include:

• Feeling unwell
• Fever
• Nausea
• Loss of appetite 
• Sleep problems
• Low mood
• Poor concentration
• Irritability
• Body pain
• Chronic fatigue
• Weight gain or loss
• Frequent infections

Management and treatment for inflammation

The management and treatment of inflammation will depend on whether it is an acute episode of inflammation or a longer-term, chronic inflammatory disorder. Inflammation, having so many different triggers, will be managed according to the system or organ affected.

Management and treatment of acute inflammation 

The management of an acute inflammatory condition could include the following⁵:

• Local or systemic anti-inflammatory drugs
• Corticosteroids or NSAIDS
• Reduce pain, fever and swelling with ice and medication
• Ensure adequate hydration levels 

Management and treatment of chronic inflammation 

Where chronic inflammation persists, a ‘cascade of inflammation’⁴ is in operation as the body reacts to the inflammation in a feedback loop. The process becomes dysfunctional and eventually becomes causative of disease. Inflammatory load can be monitored by tests; macroscopic causes such as infection and organ dysfunction can be treated, and any diseases resulting from the inflammatory process can be diagnosed.

Three general steps can be taken to manage chronic inflammation⁴:

• Help the patient understand the process that has led to their distress
• Improve the patient’s pro-inflammatory state through diet and exercise 
• Reduce symptoms 

Diet is really important in the management of chronic inflammation and also in optimising gut health. The following dietary advice may be given to remove inflammation triggers¹:

• Low-glycaemic diet
• Reduce intake of saturated fat and trans fat 
• Increase intake of omega-3 
• Reduce intake of processed foods 
• Increase intake of fruit and vegetables 
• Increase fibre 
• Consider nuts, fish oil and supplements such as curcumin 
• Increase exercise 

Medications may be used to reduce inflammation¹:

• Metformin- a type 2 diabetes medication 
• Statins
• Anti-inflammatory drugs or NSAIDs
• Corticosteroids 
• Herbal supplements- curcumin 

Diagnosis

Diagnosis of chronic inflammation 

Currently, there are no highly effective laboratory tests to diagnose chronic inflammation and often the diagnosis is made when another detectable medical condition is present that is likely to have developed due to chronic inflammation. 

Blood tests can measure the levels of inflammatory markers (proteins). Raised levels of the following proteins may signify chronic inflammation¹:

• Serum protein (measured by electrophoresis)
• High-sensitive C-reactive protein
• Fibrinogen
• Pro-inflammatory cytokines

Diagnosis of acute inflammation 

Acute inflammation will be diagnosed by the presence of the five classic signs (outlined in the signs and symptoms section) and blood tests to measure inflammatory markers. General clinical examinations will aid diagnosis in specific organs.

Complications

Complications of chronic inflammation 

Chronic inflammation is the cause of most chronic diseases.¹ As such, it is a major contributor to ill health and, if left untreated, it is likely that chronic inflammation will impact an individual’s longevity.

Chronic diseases caused by chronic inflammation¹:

• Cardiovascular disease
• Cancer
• Diabetes
• Rheumatoid arthritis
• Allergic asthma
• Chronic obstructive pulmonary disease (COPD)
• Alzheimer's disease
• Chronic kidney disease
• Inflammatory bowel disease

Complications of acute inflammation 

The main complication of acute inflammation is that if it does not resolve within six weeks then the sub-acute inflammation stage is entered which progresses to chronic inflammation.⁶

Abscesses can result from acute inflammation and tissue damage can result in fibrosis which is thickening or scarring of tissue.

Risk factors

The main risk factors for developing chronic inflammation are - 

• Increasing age
• Obesity 
• Poor diet 
• Gut dysbiosis
• Genetic predisposition 
• Lifestyle factors 
• Acute inflammation 

Risk factors that can lead to acute inflammation include infections and physical trauma.

FAQs

How can I prevent inflammation?

One of the best ways to prevent inflammation is to have a balanced and nutritionally rich diet. An anti-inflammatory diet will be high in fruit, vegetables, nuts and fibre. A diet that has high levels of good fats, including healthy fatty acids such as omega-3, as well as maintaining frequent exercise and a healthy weight, will help to reduce inflammation.

How common is inflammation?

Inflammation is incredibly common as it is a normal defence mechanism that occurs in the body. Chronic inflammation is thought to account for more than 50% of deaths worldwide.

What can I expect if I have inflammation?

Acute inflammation will cause signs and symptoms that make you feel unwell, such as redness, swelling, and localised pain. Chronic, low-grade infection may be less recognisable but will affect your quality of life by resulting in a reduced sense of well-being as discussed in the ‘signs and symptoms’ section. 

When should I see a doctor?

Make an appointment to see your doctor if your inflammation is causing severe discomfort, if youare experiencing any of the symptoms of chronic inflammation, or if you are struggling to recover from an acute inflammatory illness in conjunction with another illness . 

Summary

Inflammation is the body’s natural response to injury, infection or irritation. It involves a complex series of processes that aim to protect the body and promote healing. When tissue damage or an invading pathogen are detected, the immune response is triggered and immune cells are released to prevent further damage and begin the healing process. This very important and natural process is crucial to our survival but can in turn become damaging if it develops into a chronic state. There are many ways in which we can help to prevent chronic inflammation from damaging healthy tissue and leading to the development of chronic diseases.