5 Signs of Inflammation

Pain, Heat, Redness, Swelling, and Loss of Function

Signs of inflammation are part of the classic presentation of complaints and symptoms that healthcare providers rely on to help them make a diagnosis.

Inflammation has many causes, with how your body responds to infection among them. Five cardinal signs characterize this response: pain, heat, redness, swelling, and loss of function. In some cases, though, there may be no symptoms of inflammation at all.

This article describes two types of inflammation—acute and chronic—and details the five signs. It also discusses additional signs and complications of inflammation, as well as treatment options.

Five cardinal signs of inflammation
Verywell / JR Bee.

What Is Inflammation?  

Inflammation is a complex process involving a variety of cell and signaling proteins that protect the body from infection and foreign substances, such as bacteria and viruses. Inflammation helps the body by producing white blood cells, which your body needs to fight infection.

Sometimes, the immune system triggers an inflammatory response inappropriately. This is the case with autoimmune diseases. The body compensates by attacking its own healthy tissues, acting as if they are infected or abnormal.    

When the inflammation process starts, chemicals in white blood cells are released into the blood and the affected tissues to protect the body. The chemicals increase blood flow to the infected or injured body areas, causing redness and warmth. 

These chemicals may also cause leaking of fluids into tissues, resulting in swelling. This protective process can also stimulate nerves and tissues, causing pain. 

3 Basic Causes

The causes of inflammation are extensive but can be broadly classified as:

  • Biological, such as infections, diseases, and abnormal immune responses (including autoimmune diseases, atopy, allergy, and drug hypersensitivity)
  • Chemical, including poisons, toxins, and alcohol
  • Physical, such as injuries, burns, frostbite, or radiation exposure

Inflammation of any type can be acute or chronic.

Acute inflammation is short term in nature while chronic inflammation is long-lasting and possibly destructive.

Acute Inflammation

Acute inflammation may include heat (sometimes from fever) or warmth in the affected area. 

Acute inflammation is a healthy and necessary function that helps the body attack bacteria and other foreign substances in the body. Once the body has healed, inflammation subsides. 

Examples of conditions that cause acute inflammation include:

  • Acute bronchitis, which causes inflammation of the airways that carry air to the lungs
  • An infected ingrown toenail
  • A sore throat related to the flu
  • Dermatitis, which describes multiple skin conditions including eczema, leading to red, itchy inflamed rashes in areas where the skin flexes (such as inside the elbows and behind the knees)
  • Physical trauma
  • Sinusitis, which can cause short-term inflammation in the membranes of the nose and surrounding sinuses (usually the result of a viral infection)
  • Skin cuts and scratches

Chronic Inflammation

Chronic inflammation, on the other hand, may continue to attack healthy areas if it doesn't "turn off." It may not be as visible as acute inflammation because it includes:

Signs of Inflammation

The five cardinal signs of inflammation are common enough that you should be able to spot them immediately. They may differ in the organs that they affect, but signs of inflammation in the heart and other sites of the body share much in common.


With both acute and chronic inflammation, pain is the result of inflammatory chemicals that stimulate nerve endings, causing the affected areas to feel more sensitive.

Inflammation can cause pain in joints and muscles. When inflammation is chronic, a person will experience high levels of pain sensitivity and stiffness. The inflamed areas may be sensitive to touch. 


When inflamed areas of the body feel warm, it is because there is more blood flow in those areas.

People with arthritic conditions may have inflamed joints that feel warm to the touch. The skin around those joints, however, may not have the same warmth. Whole-body inflammation may cause fevers as a result of the inflammatory response when someone has an illness or infection.  


Inflamed areas of the body may appear red because the blood vessels of inflamed areas are filled with more blood than usual.


Swelling, or edema, is common when a part of the body is inflamed. It results from fluid accumulating in tissues either throughout the body or in the affected area.

Swelling can occur without inflammation, especially with injuries. 

Loss of Function         

Inflammation may cause loss of function related to both injury and illness. For example, an inflamed joint may not move properly, or a respiratory infection causing signs of inflammation in the lungs may make it difficult to breathe. 

Acute inflammation occurs at the onset of an injury that lasts for several days. It involves two components:

  • The cellular component, in which first-line white blood cells called leukocytes and macrophages are activated and recruited to the site of the injury
  • The vascular phase, in which blood vessels dilate (open) and tissues swell to accommodate the rapid influx of immune cells and antimicrobial chemicals

What Are Cytokines?

Cytokines released into the bloodstream lead to increased vascular permeability, or the ability of molecules to pass through blood vessels and reach tissue. Cytokines are molecules that encourage your cells to communicate with each other. A healthy immune system depends on them.

Additional Signs and Complications

When inflammation is severe, it may cause additional signs and symptoms, including:

  • Exhaustion
  • Fever
  • General feeling of sickness 

Inflammation due to illness may have dangerous complications, including a condition called sepsis. This occurs when the body's immune system overwhelmingly responds to a serious infection, which leads to generalized, life-threatening tissue damage.


it's vital to identify and treat the underlying cause of inflammation, be it infection or another issue.

In many cases, treatment includes non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids.


NSAIDs can alleviate pain associated with inflammation. They also counteract the enzymes that contribute to inflammation in order to reduce these processes. Examples of NSAIDs are Advil (ibuprofen) and Aleve (naproxen), which are available without a prescription. 

Sometimes, healthcare providers will prescribe stronger NSAIDs for people who have chronic inflammation. These include Mobic (meloxicam) and Celebrex (celecoxib).

Long-term use of NSAIDs has been associated with stomach ulcers and GI bleeding. So it's important to talk to your healthcare provider before using NSAIDs for longer than 10 days. 

NSAIDs may intensify some conditions, including asthma and kidney problems. They can also increase the risk for strokes and heart attacks.


Corticosteroids are known for preventing inflammation. There are two different types of corticosteroids: glucocorticoids and mineralocorticoids:

  • Glucocorticoids are prescribed for inflammation-producing conditions such as inflammatory arthritis, IBD, asthma, and allergic reactions. They are available in pill form, and as injections and inhalers. Creams and ointments can be prescribed to manage inflammation of the skin, eyes, and nose.
  • Mineralocorticoids are often prescribed to people with adrenal insufficiency, which happens when the adrenal glands fail to produce enough hormones.

Corticosteroid side effects are more common when taken by mouth. Inhalers and injections may reduce side effects. Inhaled medication can cause oral thrush (fungal infection) in the mouth, so rinsing with water after use is important.  

Additional side effects may include:

  • Acne
  • Blurred vision
  • Easy bruising
  • Face swelling
  • Higher blood pressure
  • Increased appetite and weight gain
  • Mood swings
  • Nervousness or restlessness
  • Stomach irritation
  • Water retention and swelling

Long-term use of corticosteroids has been associated with:

  • Cushing syndrome, a condition that results from exposure to corticosteroids. Symptoms include a fatty hump between the shoulders, purplish stretch marks, and a swelled face.
  • Heart disease
  • Osteoporosis, a bone-weakening condition
  • Ulcers and stomach bleeding


Inflammation occurs as your body fights infection. And as it wages the fight, you may experience pain, heat, redness, swelling, and loss of function.

The symptoms are common enough, but it's still smart to learn the differences between acute and chronic inflammation. It probably will make a difference in how your particular case of inflammation is treated.

A Word From Verywell

Inflammation is a necessary part of the healing process and usually nothing to worry about. But when inflammation is chronic, it can be a serious health problem. See your healthcare provider to identify the source of the inflammation. It's the first step toward proper treatment.

Frequently Asked Questions

  • What can I drink to reduce inflammation?

    Water, tea, coffee, milk, acidic juices, smoothies, and moderate amounts of alcohol (specifically red wine) can help fight inflammation. Avoid sugary drinks and sodas.

  • What are the worst foods for inflammation?

    Anti-inflammatory foods to avoid include white bread and pastries made with refined flours, fried foods (including potatoes), red and processed meats, like beef and sausage, and margarines.

  • Can inflammation affect internal organs?

    Over time, chronic inflammation can cause changes in organs that may increase the risk of heart attack, cancers, and other age-related diseases. Chronic inflammation is associated with chronic condition like diabetes, heart disease, COPD, or HIV.

  • How do you test for inflammation?

    Testing for inflammation will depend on your healthcare provider's assessment and what the suspected source may be. Blood tests, allergy skin tests, and gastrointestinal (GI) procedures are just a few of the possible tests.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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