What causes inflammation? Diagnosis, prevention, and treatment

Medically reviewed by Leslie GreenbergMD
Board-Certified Family Physician
Updated Oct. 27, 2023  •  Published Jun. 20, 2023
Fact Checked
Causes of inflammation

Overview: What is inflammation?

Inflammation is the body’s natural response to injury, infection, or damage. When the body’s tissues are damaged, infected, or invaded, the immune system activates, sending out chemical fire alarms called cytokines which initiate the inflammatory response and bring immune cells to the site. Inflammation is the body’s initial attempt to isolate pathogens to prevent them from infecting other body parts. White blood cells then fight off the pathogen and clean up the toxins and dead tissues, allowing the body to start the healing process. 

The inflammatory response can cause swelling, redness, and pain. If the injury or infection affects much of the body, the inflammatory response can result in fever, fatigue, and aches and pains. Though it isn’t comfortable to experience, inflammation is usually a good thing unless it gets severe or doesn’t go away. There are two types of inflammatory responses. Acute inflammation happens when the body responds to a new infection or injury. The timeline of inflammation has a clear beginning and ends, usually in a few days or weeks. However, sometimes the immune system does not appreciate the negative feedback and turns itself off. Sometimes it mistakenly goes after healthy tissues or substances usually found in the body. The inflammatory response can keep happening over and over again, but it’s not beneficial to the body’s health. Called chronic inflammation, this repeated inflammatory response can cause damage to tissues and organs.

Key takeaways:

  • Inflammation is a common health condition affecting anyone regardless of age, sex, race, or ethnicity. 

  • Infections, injuries, allergies, autoimmune disorders, diabetes, heart disease, and cancer cause inflammation.

  • Risk factors for inflammation include exposure to infections, autoimmune conditions, allergies, age, obesity, diet, smoking, stress, sleep problems, and low sex hormones.

  • Symptoms of inflammation include swelling, redness, warmth, pain, loss of body function, body aches, joint pain, muscle pain, fatigue, difficulty sleeping, weight changes, mood disorders (depression, anxiety), and gastrointestinal complaints.

  • Acute inflammation is typically self-diagnosable, but chronic inflammation usually requires a medical diagnosis.

  • Inflammation may or may not require treatment. Acute inflammation typically resolves with or without treatment in a few days or weeks, but chronic inflammation is more variable.

  • Treatment of inflammation includes rest, ice, over-the-counter medications, corticosteroids, immune-suppressing drugs, and treating the underlying cause. 

  • Inflammation is partly preventable by dietary changes, lifestyle changes, weight loss, exercise, and avoiding triggers.

  • Use coupons for inflammation treatments, such as aspirin, Advil (ibuprofen), Aleve (naproxen), and prednisone, to save up to 80%.

What causes inflammation?

Causes of inflammation vary depending on whether the swelling is acute or chronic. Acute inflammation—a temporary case of inflammation—is usually caused by injury or invasion. The most common causes are:

  • Microbes such as bacteria, viruses, and funguses

  • Foreign objects, irritants, and poisons

  • Dead tissues

  • Damaged, stressed, or malfunctioning tissues (such as a cut, a burn, torn ligament, a broken bone, or radiation exposure)

Medical procedures both simple and complex are a common source of acute inflammation. Teeth cleaning, injections, and vaccines can all cause swelling and redness. Acute inflammatory responses following surgical procedures are more serious. People will often be monitored after surgery for complications, including inflammation.

Chronic inflammation causes are much more varied. Chronic inflammatory conditions include:

RELATED: A new tool could predict a person’s risk of developing a chronic disease

Risk factors for inflammation

Acute inflammation is caused by infections, injuries, and exposure to foreign substances, so there are no specific risk factors other than exposure to infections, behaviors that increase the risk of injury, overexercise, and allergies. 

Chronic inflammation is a more serious condition because it can eventually damage the body’s tissues, sometimes irreparably. Risk factors for chronic inflammation include:

  • Increasing age

  • High body mass index (BMI)

  • Smoking

  • Exposure to dust, chemicals, or pollutants

  • Increased stress

  • Sleep disorders

  • Low sex hormones

Is inflammation serious? When to see a doctor

People experience inflammation all the time. Cuts, bruises, bumps, allergic reactions, and mild infections occur commonly and are aspects of being alive. Most of these conditions don’t require medical attention. Both the inflammation and the underlying problem typically get better without intervention.

Body-wide severe symptoms of acute inflammation such as high fever are a sign to get medical care. These symptoms usually mean that the underlying problem is serious, and the inflammatory response itself may be doing harm. An extremely high fever requires immediate medical attention. 

Acute inflammation is a natural response to injuries, but some injuries require immediate medical attention, depending on the severity of the injury.

Anyone with symptoms of acute organ inflammation requires immediate medical care. Acute inflammation of the pancreas (pancreatitis), liver (hepatitis), brain (meningitis or encephalitis), or heart (myocarditis) are all considered medical conditions in their own right. Because inflammation of these organs disrupts their vital functions, these conditions will have unique symptoms that aren’t like those of a cut or allergic reaction. 

People with chronic inflammation should see a healthcare professional for evaluation. Some people with chronic inflammatory conditions don’t realize their symptoms are due to chronic inflammation. The symptoms may seem like a digestive system, nerve, or muscle problem. It’s essential to get a diagnosis to get the appropriate treatment. Treatments focus on decreasing inflammation and controlling the immune response. 

RELATED: 10 signs of inflammation to watch out for

How is inflammation diagnosed?

Inflammation itself is typically not diagnosed. Instead, the healthcare professional discovers the underlying medical condition causing the inflammation. Depending on the symptoms and medical history, the healthcare provider will perform certain physical examinations, medical imaging, and tests. Sometimes, a blood test will be used to determine if there is an inflammatory response and how bad it is. These tests look for various inflammatory markers in the blood, but the standard test measures C-reactive protein (CRP) levels. A healthcare provider may order a CRP blood test for signs of a serious bacterial infection, viral infection, sepsis, or a chronic inflammatory condition. A CRP test may also be used to monitor the effectiveness of treatment.

RELATED: What are normal CRP levels?

Is inflammation hereditary? 

Some conditions that cause acute inflammation, such as allergies, diabetes, or autoimmune diseases like lupus, have a genetic component. Some are strongly inheritable, but sometimes chronic conditions are due to genetics and environmental factors. These conditions are partly preventable and controllable with lifestyle changes and certain preventive measures. 

RELATED: Why is family health history important?

Is inflammation curable?

Because acute inflammation is beneficial when limited, little treatment is needed outside of symptom relief:

Some conditions that cause acute inflammation may have other anti-inflammatory treatments, such as antihistamines or decongestants for allergies or upper respiratory infections. These OTC medications fight one part of the inflammatory response: antihistamines by blocking histamine and decongestants by reducing blood flow to the inflamed area. 

Other conditions that cause acute inflammation may require treatment on top of symptom relief. For instance, healthcare providers may prescribe antibiotics for bacterial infections.

Chronic inflammation may require treatment both during and between flare-ups. The standard treatments include:

  • Dietary changes

  • Dietary supplements

  • NSAIDs

  • Oral corticosteroids

  • Steroid injections

  • Immune-suppressing drugs and biologics

Some chronic inflammation causes may have specific treatments on top of inflammation therapies. These include surgery for inflammatory bowel disease, anticancer drugs for cancer, or drugs that lower blood sugar for Type 2 diabetes.

RELATED: What are the best OTC anti-inflammatory drugs

How to prevent inflammation

Acute inflammation is usually beneficial and hard to avoid. However, chronic inflammation is unpleasant to live with and can damage the body’s tissues. Several lifestyle changes can help prevent chronic inflammation and improve one’s overall health:

  • Adopt a healthy diet such as the Mediterranean diet that is low in sugars, processed foods, saturated fats, and trans fats

  • Lose weight

  • Quit smoking

  • Reduce alcohol intake

  • Exercise regularly

  • Practice good sleep hygiene

  • Reduce emotional stress

RELATED: How to reduce inflammation in the body fast

Most importantly, eat to prevent inflammation

If inflammation is an ongoing problem, one of the most effective ways to reduce and prevent inflammation is to adopt an anti-inflammatory diet. The recommended diet for inflammation follows a few simple rules:

  • Reduce the amount of high glycemic foods such as sugar and refined carbohydrates

  • Avoid saturated fats and trans fats such as those found in fried foods, but olive oil is okay

  • Avoid processed and packaged foods

  • Increase your intake of anti-inflammatory foods high in antioxidants, such as vegetables, fruits, and almonds

  • Increase the amount of fiber in the diet

  • Increase your intake of fish oils and omega fatty acids

  • Drink green and black tea—both have been shown to reduce CRP in the body

  • Take turmeric or curcumin supplements

  • Increase the amount of fish oil and sesame oil in the diet

RELATED: What’s the best diet for inflammation?

FAQs about inflammation causes

What are the five warning signs of inflammation?

The five distinctive signs of inflammation are swelling, redness, warmth, pain, and loss of function. 

What happens if you have too much inflammation in your body?

Inflammation is the body’s defense mechanism, but sometimes it can hurt the body. Chronic inflammation can steadily damage the body’s tissues, leading to severe health conditions like cardiovascular disease, cancer, stroke, or Type 2 diabetes. Though limited, acute inflammation can sometimes harm or kill the body. Acute inflammation could land a person in the hospital if a vital organ is affected, such as the liver, heart, or pancreas. It may also do serious damage that leads to lasting complications or death. An acute inflammatory response sometimes runs out of control, resulting in severe illness and death. The best-known examples include sepsis and acute respiratory distress syndrome (ARDS), one of the leading causes of death in people with COVID-19.

What infections cause inflammation?

Inflammation is the body’s defense against bacterial, viral, parasite, and fungal infections. Not only does inflammation help marshal the immune system to fight the infection, but many of the symptoms of inflammation, such as warmth and swelling, help to contain the infection, preventing it from spreading to other parts of the body.

What’s next? Additional resources for people with inflammation

Test and diagnostics

Treatments

Scientific studies and clinical trials

Medically reviewed by Leslie GreenbergMD
Board-Certified Family Physician

Leslie Greenberg, MD, is a board-certified practicing family physician with more than 25 years of doctoring experience. She was a psychology major at Northwestern University near Chicago, then graduated with an MD from the University of Nevada School of Medicine. She completed her family medicine residency at St. Joseph Hospital in Wichita, Kansas. She has trained more than 350 family medicine resident-physicians, been in private practice, and delivered babies for 22 years.

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