5 Cardinal Signs of Inflammation

A cardinal sign is a major symptom that doctors utilize to make a diagnosis. In the case of inflammation, there are five cardinal signs that characterize the condition: pain, heat, redness, swelling, and loss of function.

Interestingly, inflammation is a biological process that your body uses in response to infection. It is important to note, however, that not all five cardinal signs are present in every instance of inflammation. Moreover, the inflammatory process could be silent and not cause noticeable symptoms.

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 and other substances.

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 in those locations. 

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

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 to attack bacteria and other foreign substances anywhere 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.
• Skin cuts and scratches.
• Dermatitis, which describes multiple skin conditions including eczema, which causes red, itchy inflamed rashes in areas where the skin flexes (such as inside the elbows and behind the knees).
• Sinusitis, which can cause short-term inflammation in the membranes of the nose and surrounding sinuses (usually the result of a viral infection)
• Physical trauma.

Chronic Inflammation

Chronic inflammation, on the other hand, may continue to attack healthy areas if it doesn't turn off. It can occur anywhere in the body and may trigger any number of chronic diseases, depending on the area of the body affected. 

Examples of conditions that cause chronic inflammation include:

• Inflammatory arthritis, which covers a group of conditions distinguished by inflammation of joints and tissues (including rheumatoid arthritis, lupus, and psoriatic arthritis).
• Asthma, which causes inflammation of the air passages that carry oxygen to the lungs. Inflammation causes these airways to become narrow and breathing to become difficult. 
• Periodontitis, which causes inflammation of gums and other supporting teeth structures. It is caused by bacteria triggered by local inflammation.
• Inflammatory bowel disease (IBD). IBD refers to Crohn’s disease and ulcerative colitis. Both these conditions cause chronic inflammation in the gastrointestinal (GI) tract that eventually causes damage to the GI tract. 

Cardinal Signs 

There are five cardinal signs of inflammation, though it may also cause additional symptoms if severe.

Pain

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. 

Heat

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.  

Redness 

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

Swelling 

Swelling is common when a part of the body is inflamed. It is the result of fluid accumulating in tissues either throughout the body or in the specific 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 cannot be moved properly, or it can make it difficult to breathe due to a respiratory infection. 

The reason for all these symptoms is the same: Cytokines released into the bloodstream lead to increased vascular permeability to allow migration of immune cells into tissues.

Additional Signs and Complications

When inflammation is severe, it may cause additional signs and symptoms. This may include fever, a general feeling of sickness, and exhaustion. 

Sepsis occurs when the body's immune system overwhelmingly responds to a serious infection, which leads to generalized, life-threatening tissue damage.

Treatment 

Common treatments for inflammation include non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids, though it's also important to identify and treat the underlying cause of inflammation, be it infection or another issue.

NSAIDs

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

Sometimes, doctors will prescribe stronger NSAIDs for people who have chronic inflammation, including medications such as, Mobic (meloxicam) and Celebrex (celecoxib).

Long-term use of NSAIDs has been associated with stomach ulcers and GI bleeding, so it is important to talk to your doctor before using NSAIDs for longer than 10 days. NSAIDs may also worsen some conditions, including asthma and kidney problems. They also increase the risk for strokes and heart attacks.

Corticosteroids

Corticosteroids are known for preventing inflammation processes. 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, but creams and ointments can be prescribed to manage inflammation of the skin, eyes, and nose.

Mineralocorticoids, the second type of corticosteroid, are often prescribed to people with adrenal insufficiency.

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

Additional side effects, according to the Cleveland Clinic, include:

• Increased appetite and weight gain.
• Mood swings.
• Easy bruising.
• Blurred vision.
• Increased body hair.
• Decreased resistance to infection.
• Swelling in the face.
• Acne.
• Stomach irritation.
• Nervousness and restlessness.
• Problems sleeping.
• Water retention and swelling.
• Increased blood pressure.
• Worsening diabetes symptoms.

Long-term use of corticosteroids has been associated with:

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

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. Anyone experiencing ongoing inflammation should talk to their doctor about determining the source of inflammation and getting appropriate treatment to avoid any serious complications.