Inflammation is a key aspect of the body’s immune defenses. It can be acute or chronic. Symptoms can include swelling, heat, pain, and more. Treatments can depend on the underlying cause.

The body may send cells to defend against a foreign body, such as a thorn, an irritant, or a pathogen. Pathogens include bacteria, viruses, and other organisms, that cause infections.

Sometimes, the body mistakenly perceives its own cells or tissues as harmful. This reaction can lead to autoimmune diseases, such as type 1 diabetes.

Experts believe inflammation may contribute to a wide range of chronic diseases. Examples of these are metabolic syndrome, which includes type 2 diabetes, heart disease, and obesity.

People with these conditions often have higher levels of inflammatory markers in their bodies.

In this article, find out more about why inflammation happens, its symptoms, and ways to resolve it.

a woman holding her hand because she has pain there from inflammationShare on Pinterest
A person with acute inflammation might experience pain in the affected area.

There are two main types of inflammation: acute and chronic.

Acute inflammation

An injury or illness can involve acute, or short-term, inflammation.

There are five key signs of acute inflammation:

  • Pain: This may occur continuously or only when a person touches the affected area.
  • Redness: This happens because of an increase in the blood supply to the capillaries in the area.
  • Loss of function: There may be difficulty moving a joint, breathing, sensing smell, and so on.
  • Swelling: A condition called edema can develop if fluid builds up.
  • Heat: Increased blood flow may leave the affected area warm to the touch.

These signs are not always present. Sometimes inflammation is “silent,” without symptoms. A person may also feel tired, generally unwell, and have a fever.

Symptoms of acute inflammation last a few days. Subacute inflammation lasts 2–6 weeks.

Chronic inflammation can continue for months or years. It either has or may have links to various diseases, such as:

The symptoms will depend on the disease, but they may include pain and fatigue.

Measuring inflammation

When inflammation is present in the body, there will be higher levels of substances known as biomarkers.

An example of a biomarker is C-reactive protein (CRP). If a doctor wants to test for inflammation, they may assess CRP levels.

CRP levels tend to be higher in older people and those with conditions such as cancer and obesity. Even diet and exercise may make a difference.

Inflammation happens when a physical factor triggers an immune reaction. Inflammation does not necessarily mean that there is an infection, but an infection can cause inflammation.

Acute inflammation

Acute inflammation can result from:

  • exposure to a substance, such as a bee sting or dust
  • an injury
  • an infection

When the body detects damage or pathogens, the immune system triggers a number of reactions:

  • Tissues accumulate plasma proteins, leading to a buildup of fluid that results in swelling.
  • The body releases neutrophils, a type of white blood cell, or leukocyte, which move toward the affected area. Leukocytes contain molecules that can help fight pathogens.
  • Small blood vessels enlarge to enable leukocytes and plasma proteins to reach the injury site more easily.

Signs of acute inflammation can appear within hours or days, depending on the cause. In some cases, they can rapidly become severe. How they develop and how long they last will depend on the cause, which part of the body they affect, and individual factors.

Some factors and infections that can lead to acute inflammation include:

Chronic inflammation

Chronic inflammation can develop if a person has:

  • Sensitivity: Inflammation happens when the body senses something that should not be there. Hypersensitivity to an external trigger can result in an allergy.
  • Exposure: Sometimes, long-term, low-level exposure to an irritant, such as an industrial chemical, can result in chronic inflammation.
  • Autoimmune disorders: The immune system mistakenly attacks normal healthy tissue, as in psoriasis.
  • Autoinflammatory diseases: A genetic factor affects the way the immune system works, as in Behçet’s disease.
  • Persistent acute inflammation: In some cases, a person may not fully recover from acute inflammation. Sometimes, this can lead to chronic inflammation.

Factors that may increase the risk of chronic inflammation include:

Long-term diseases that doctors associate with inflammation include:

Inflammation plays a vital role in healing, but chronic inflammation may increase the risk of various diseases, including some cancers, rheumatoid arthritis, atherosclerosis, periodontitis, and hay fever.

The following table summarizes some key differences between acute and chronic inflammation.

AcuteChronic
CauseHarmful pathogens or tissue injury. Pathogens that the body cannot break down, including some types of viruses, foreign bodies that remain in the system, or overactive immune responses.
OnsetRapid.Slow.
DurationA few days.From months to years.
OutcomesInflammation improves, or an abscess develops or becomes chronic.Tissue death, thickening, and scarring of connective tissue.

It is essential to identify and manage inflammation and related diseases to prevent further complications.

Treatment of inflammation will depend on the cause and severity.

In terms of acute inflammation, a doctor may prescribe treatment to remove the cause of inflammation, manage symptoms, or both.

Acute inflammation

Nonsteroidal anti-inflammatory drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) will not remove the cause of inflammation, but they can help relieve pain, swelling, fever, and other symptoms. They do this by countering an enzyme that contributes to inflammation.

Examples of NSAIDs include naproxen, ibuprofen, and aspirin.

People should only use NSAIDs long term if a doctor recommends them, as they can have adverse effects. Aspirin is not suitable for children.

Pain relief

Acetaminophen, including paracetamol or Tylenol, can relieve pain but does not reduce inflammation. These drugs allow the inflammation to continue its role in healing.

Corticosteroids

Corticosteroids, such as cortisol, are a type of steroid hormone. They affect various mechanisms involved in inflammation.

Corticosteroids can help manage a range of conditions, including:

Long-term use of corticosteroids can be harmful. A doctor can advise on their risks and benefits.

Treatment for diseases that involve long-term inflammation will depend on the condition.

Some drugs act to repress the body’s immune reactions. These can help relieve symptoms of rheumatoid arthritis, psoriasis, and other similar autoimmune reactions. However, they can also leave a person’s body less able to fight an infection if it occurs.

People who have undergone transplant surgery also need to take immunosuppressant drugs to prevent their bodies from rejecting the new organ. They, too, need to take extra care to avoid exposure to infections.

Various herbal supplements, such as the following, are shown to have anti-inflammatory properties:

These herbs are not approved by the Food and Drug Administration (FDA) for medicinal use. A person should always talk to a doctor before using any herbal or other supplements.

Some foods contain nutrients that may help reduce inflammation.

They include:

Diet alone will not control inflammation, but making suitable choices may help prevent it from getting worse.

Learn more here about the anti-inflammatory diet.

Below are some frequently asked questions about inflammation.

What are the five signs of inflammation?

The five signs of acute inflammation are:

  • pain
  • redness
  • swelling
  • heat
  • loss of function

What are the three main causes of inflammation?

Three potential causes of acute inflammation are:

  • injury
  • infection
  • exposure to a substance, such as a bee sting

How can someone rid the body of inflammation?

Treatment for inflammation may depend on the cause. However, people can also take steps such as eating an anti-inflammatory diet and taking herbal supplements, such as ginger or turmeric.

What is the fastest way to flush inflammation?

Over-the-counter NSAIDs, such as naproxen (Aleve), ibuprofen (Advil), and aspirin, can help to quickly relieve the symptoms of inflammation, such as pain and swelling. However, this treatment will not remove the cause of inflammation.

Inflammation is part of the process by which the immune system defends the body from harmful agents, such as bacteria and viruses.

Acute inflammation is triggered by injury, infection, or exposure to substances, and presents itself as pain, redness, swelling, loss of function, and heat.

Long-term or chronic inflammation, however, can both lead to and result from some severe and possibly life threatening conditions. It is linked to various diseases, including diabetes, cardiovascular issues, and autoimmune disorders.

Treatments for both acute and chronic inflammation include NSAIDs, pain relief, corticosteroids, and immune-suppressing drugs. Herbal supplements and diet may also help to relieve symptoms of inflammation.