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What Is Inflammation And What Causes It?
Updated on December 30, 2022
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At Home Health
What Is Inflammation And What Causes It?

The immune system is our body’s defense mechanism against threats. It strives to eliminate any offending agents that enter our bodies. 

As soon as the body sustains an injury, the immune system attempts to repair the damaged tissues. These protective and healing processes trigger inflammation. 

According to our in-house health expert Dr. Rizza Mira, inflammation “can be acute or chronic. Acute injuries can cause long-term inflammation. Chronic inflammation also can have acute bouts of the condition.”

Our body’s immune response to harmful stimuli involves the right kind of inflammation. But a prolonged inflammatory response isn’t natural and can lead to health complications like chronic inflammation.

What Is Inflammation And What Causes It? 2

What Is Inflammation?

Inflammation is the body’s natural response when it detects:

  • Irritants like foreign objects
  • Infectious pathogens like bacteria or viruses
  • Injuries
  • Toxins
  • Stress

These stimuli alert your immune system to send inflammatory cells and other blood cells to injuries or potential foreign bodies. They will either trap the bacteria (or other offending agents) or initiate the healing process of tissue injury. 

The immune system also makes blood cells called cytokines and interleukins. Cytokines are proteins that stimulate immune system cell production.1 Interleukins regulate the immune system.

Types Of Inflammation

Inflammation has two types: acute and chronic. They differ depending on how long the inflammatory response lasts.

Acute inflammation 

Acute inflammation is a short-lived inflammation. It occurs when there’s immediate damage to your body. It starts rapidly and may become severe for minutes to hours to days, depending on the injury. 

“Some acute inflammatory conditions are also the pathway to chronic inflammation,” says Dr. Mira.

Under acute inflammation, your immune system sends inflammatory cells to the injured site. These cells will start the healing. 

You’ll notice pain, swelling, redness, or bruising at the injury site. The symptoms may last for a few days up to two weeks.2 

An example of acute inflammation is cellulitis. Cellulitis is a bacterial skin infection that causes inflammation of the skin's connective tissue.

Most symptoms of cellulitis, like swelling, redness, and pain, typically disappear within the first three days of taking antibiotic medications. Your cellulitis should improve within seven to 10 days. 

Chronic inflammation 

Chronic inflammation is also known as slow, long-term inflammation. It lasts for several months to years. 

It occurs when the inflammatory response is continuous, even when the threat is gone.4 The extent of chronic inflammation depends on the cause of your injury. 

“Some chronic inflammatory conditions can also have worsening acute attacks. Medications, like steroids, can help to prevent acute attacks from becoming chronic,” says Dr. Mira.

Chronic inflammation may occur due to 

  • Infections that don't go away
  • Abnormal immune reactions to healthy tissues
  • Health conditions like obesity

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How Inflammation Works

Inflammation starts when the body tries to fight a harmful irritant. Your white blood cells (WBCs) release chemicals that surround the antigens or foreign substances and defend your body. This process of protecting the body from antigens causes:

  • Redness and warmth from the increase of blood flow to the injured or infected site
  • Swelling from fluids leaking into your tissues
  • Pain from triggered nerves

For example, your joints may become irritated when there are too many WBCs. The inflammatory chemicals produced by WBCs also contribute to the irritation. 

They can inflame the joint lining (synovium) and wear down the cartilage. Over time, the joint lining may become swollen and create increased friction between the joints, causing pain.  

How To Tell If You Have Inflammation

The symptoms depend on whether you have acute or chronic inflammation. 

Signs of Acute Inflammation

These are the signs of acute inflammation:5

  • Skin redness at the site of injury or wound
  • Pain
  • Swelling
  • The location of injury or wound is warm to touch
  • Fever

Signs of Chronic Inflammation

Chronic inflammation can be harder to detect. Its signs vary depending on your condition. 

These are the general symptoms of chronic inflammation:5

  • Abdominal and chest pains
  • Fatigue
  • Fever
  • Joint pains
  • Weight loss 
  • Skin rash
  • Changes in bowel movement

If you’re experiencing any of these symptoms, you should see a doctor for a more extensive diagnosis.

What Causes Acute Inflammation?

Many things can cause acute inflammation. But the two leading causes are external and internal signals.

External (exogenous) triggers are from damage caused by a foreign stimulus. Examples of external triggers are:6 

  • Bacteria
  • Viruses
  • Allergens
  • Toxic compounds
  • Foreign bodies that are too large for the body to digest

On the other hand, internal (endogenous) signals are triggered by dead, damaged, or stressed tissues.6 

“As part of the body's metabolic process, oxygen-free radicals are produced. However, too much production of these substances can also damage the tissues,” says Dr. Mira. 

In some cases, the body may still see dead or dying tissues as threats. It sends signals so the inflammatory cells can clear dead tissues, making way for new tissues. 

The inflammatory response also promotes the repair of damaged or stressed tissues. 

What Causes Chronic Inflammation?

Chronic inflammation occurs due to these reasons:

  • Autoimmune diseases, such as lupus
  • Long-term exposure to industrial chemicals and pollution
  • Failure to treat acute inflammation from infection or injury

An autoimmune disorder is when your immune system attacks healthy tissue, mistaking it for a threat. 

Factors That Increase Your Risk

Your lifestyle can increase your risk of developing chronic inflammation. The following factors contribute to inflammation in the body:

  • Excessive alcoholic intake
  • A body mass index (BMI) of 30 or higher. Doctors consider this to be under the obese range.
  • Extremely intense work-outs that are too frequent
  • Lack of exercise
  • Chronic stress
  • Smoking

Conditions Linked To Chronic Inflammation

The inflammatory response is natural in many diseases and conditions. For instance, inflammation causes soreness in your throat when you have a cold. 

It indicates that your body is fighting an antigen. Your symptoms will disappear shortly, and your body will return to normal after a while. 

However, chronic inflammation means you have ongoing inflammation, and either your body is taking longer to return to its original state, or your immune system is causing an exaggerated response. This prolonged inflammation may cause you to develop an inflammatory disease.2

Health experts link many chronic diseases to chronic inflammation. The most common among them are:7

  • Fatty liver disease
  • Endometriosis
  • Type 1 diabetes mellitus
  • Type 2 diabetes mellitus
  • Inflammatory bowel disease (IBD)
  • Asthma
  • Rheumatoid arthritis
  • Obesity
  • Alzheimer’s and Parkinson’s diseases
  • Cancer

How to treat inflammation

Treatments like medications aren't always required when you have inflammation. You can relieve acute inflammation by applying ice or other topical solutions. Good wound care also eases inflammation. 

However, you need to visit your doctor if you have chronic inflammation. Depending on your condition, they may prescribe:

  • Supplements, such as vitamins A, C, and D, and zinc supplements lessen the inflammation in the body. These nutrients can also expedite tissue repairs.
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) for pain relief.
  • Oral steroid medications.
  • Steroid injections that relieve inflammation at a specific joint or muscle.

“Most chronic inflammatory conditions, like asthma, Rheumatoid arthritis, IBD, and cancers, need some form of immunosuppressant to maintain the disease in a quiet state,” says Dr. Mira.

How to naturally reduce inflammation

Lifestyle changes can help reduce inflammation in the body. You can start by switching to an anti-inflammatory diet. 

You may add anti-inflammatory foods to your meals, like green leafy vegetables, olive oil, and tomatoes.7 

Oily fish like sardines, mackerel, and salmon also have anti-inflammatory properties.7 

Certain foods may cause inflammation. If you have chronic inflammation, it’s best to avoid consuming these foods:7

  • Fried foods
  • Fast foods
  • Meats cured with nitrates like hotdogs
  • Trans fats
  • Highly-refined oil
  • Refined carbohydrates, such as sugar, pastries, or white bread

Healthier food choices combined with exercise can make an impact on reducing the inflammation in your body. 

Quitting unhealthy habits like excessive alcohol intake and cigarette smoking can also contribute to your healing.

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Updated on December 30, 2022
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8 sources cited
Updated on December 30, 2022
  1. Cytokines, Inflammation and Pain.” International Anesthesiology Clinics.
  2. Acute Inflammatory Response.” National Center for Biotechnology Information.
  3. Cellulitis.” Mount Sinai.
  4. Chronic Inflammation.” National Center for Biotechnology Information.
  5. Inflammation.” Cleveland Clinic.
  6. Chronic Inflammation.” National Center for Biotechnology Information.
  7. Some common inflammatory diseases.” The University of Queensland.
  8. Foods that fight inflammation.” Harvard Health Publishing.
Dr. Rizza Mira
Dr. Rizza Mira
Medical Reviewer
Dr. Rizza Mira is a medical doctor and a general practitioner who specializes in pediatrics, nutrition, dietetics, and public health.

As a pediatrician, she is dedicated to the general health and well-being of children and expecting parents. She believes that good nutrition, a healthy lifestyle, and prevention of illness are key to ensuring the health of children and their families.

When she’s not in the hospital, Rizza advocates and mobilizes causes like breastfeeding, vaccination drives, and initiatives to prevent illness in the community.
Cristine Santander
Cristine Santander
Content Contributor
Cristine Santander is a content writer for KnowYourDNA. She has a B.S. in Psychology and enjoys writing about health and wellness.
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