The immune system is an intricate network of organs, cells, proteins, and chemicals that protect the body from internal and external harmful elements. Inflammation is a vital process in our immune system’s natural response to threats. In its acute phase, it is necessary and beneficial. However, when it turns into a systemic, chronic condition, it can lead to damage.

This article focuses on the differences between acute and chronic inflammation, helping you understand how to recognize and treat them.

What Is Acute Inflammation?

Acute inflammation is the body’s natural response to infection, disease, or injury. It involves an increased migration of leukocytes (white blood cells) and proteins to the zone of the injured area to combat pathogens and repair cells and tissues. Increased blood flow typically causes redness, swelling, warmth, and tingling. Patients also feel pain at the site of injury.

Acute inflammation is a vital and beneficial part of the healing process. It subsides when the assaulting agent (pathogen, injury, etc.) is eliminated.

Types of Acute Inflammation

Medical professionals recognize six types of acute inflammation based on the discharge present at the inflammation site:

• Serous – Characterized by the presence of watery, yellowish, serum-like fluid. It forms in the early stages of inflammation.
• Fibrinous – Increased vascular permeability allows the protein fibrinogen to escape into extravascular space, creating a thick exudate and impeding blood flow. It forms in the advanced stages of inflammation.
• Catarrhal – Affects the mucous membrane and causes excessive secretion (e.g., runny nose).
• Purulent – Involves the formation of an abscess - a large, thick mass filled with puss, typically caused by bacteria.
• Hemorrhagic – Characterized by exudate filled with blood from damaged blood vessels. It forms due to severe injury or lack of coagulation factors.
• Gangrenous – Involves tissue necrosis (death of tissue cells) and gangrene due to a loss of blood and oxygen supply to the inflammation site. It is associated with severe infections.

What Is Chronic Inflammation?

Chronic inflammation is the body’s prolonged defense reaction to a perceived threat – a pathogen, allergen, toxin, or some other invasive factor. It appears when the body fails to resolve the threat or mistakenly perceives healthy tissues as harmful elements. Instead of affecting a particular area, chronic inflammation produces a systemic response, constantly stimulating the increased production of leukocytes, cytokines, and other pro-inflammatory mediators. Eventually, it destroys tissues, organs, and blood vessels.

Types of Chronic Inflammation

Scientists recognize two types of chronic inflammation:

• Granulomatous – Characterized by clusters of white blood cells (granulomas), which form as the immune system’s reaction to a foreign element it can’t eliminate. It is often caused by a chronic infection or an autoimmune condition.
• Nonspecific – An unidentifiable irritating agent causes a diffuse immune response, leading to the formation of nonspecific granulation tissue and healing by fibrosis (formation of scar tissue).

How Does Acute Inflammation Differ from Chronic Inflammation?

Acute and chronic inflammation differ in severity, symptoms, duration, and treatment. The following table summarizes their differences.

Examples of Acute vs. Chronic Inflammation

The following examples can help you distinguish between the two inflammation types.

Acute Inflammation

The body’s essential inflammatory immune response appears when we suffer from the following conditions:

• Sore throat
• Acute bronchitis
• Sinusitis
• Pneumonia
• Acute tonsilitis
• Acute appendicitis
• Ingrown toenail
• Insect bites
• Acute dermatitis, etc.

Chronic Inflammation

Chronic inflammation is linked to these inflammatory diseases:

• Type 2 diabetes
• Obesity
• Heart disease
• Kidney disease
• Rheumatoid arthritis
• Ankylosing spondylitis
• Lupus
• Autoimmune thyroiditis
• Crohn’s disease
• Depression
• Anxiety, etc.

Acute vs. Chronic Inflammation Symptoms

Inflammatory symptoms strongly indicate whether the condition is acute or chronic.

Acute Inflammation

The symptoms of acute inflammation are intense, short-lived, and typically localized at the site of injury or infection. They include:

• Redness
• Swelling
• Heat
• Pain
• Loss of function

Chronic Inflammation

Chronic inflammation symptoms may go unnoticed for a long time. When they appear, they manifest as:

• Bloating and gas
• Diarrhea
• Constipation
• Weight gain
• Irritability
• Depression
• Fatigue
• Insomnia
• Joint pain
• Premature skin aging (wrinkles, dryness, etc.)

Acute vs. Chronic Inflammation Causes

The causes of acute and chronic inflammation differ. Unresolved acute inflammation can lead to chronic conditions.

Acute Inflammation

Common causes of acute inflammation include:

• Cuts
• Physical trauma
• Burns
• Frostbite
• Bacterial or viral infection
• Toxins
• Chemical irritants
• Allergens

Chronic Inflammation

Factors leading to or perpetuating chronic inflammation include:

• Unhealthy diet
• Lack of physical activity
• Excess weight
• Alcohol
• Nicotine
• Environmental pollutants
• Sleep disorders
• Chronic stress
• Autoimmune disorders

Acute vs. Chronic Inflammation Diagnosis

Acute and chronic inflammation exhibit different symptoms and recruit different concentrations of inflammatory cells and proteins, such as interleukins, tumor necrosis factors, and C-reactive protein. This enables medical providers to establish whether acute or chronic inflammation is present.

Acute Inflammation

Medical providers physically examine the patient, discuss their symptoms and potential causes, and review their medical history. Acute inflammation is easy to spot due to apparent, intense, localized symptoms like swelling, redness, and pain.

They may also order blood tests, such as:

• Complete blood count (CBC) – The most common test routinely performed for any infection. In acute inflammation, lab results typically show neutrophils as the predominant biomarkers. They are short-lived white blood cells that rush to the injury site as the body’s initial defense response. Lymphocytes may also be present in the results.
• C-reactive protein (CRP) – Measures the level of the protein produced by the liver. High levels of CRP indicate acute or chronic inflammation.
• Erythrocyte sedimentation rate (ESR) – Measures the rate of red blood cell sedimentation in a blood test tube. Faster sedimentation indicates inflammation.
• Ferritin – Measures the level of the protein ferritin, which stores iron in our cells. Doctors may order this test in the presence of chronic inflammation symptoms, such as joint pain, heart issues, abdominal pain, and more.

Chronic Inflammation

In chronic inflammation, macrophages and lymphocytes typically replace neutrophils. They stimulate the release of other inflammatory mediators that serve as the next line of defense, such as cytokines, growth factors, enzymes, and plasma cells, and form clusters of white blood cells called granuloma.

A blood test showing increased levels of these biomarkers can indicate chronic inflammation. The blood tests are the same as those for acute inflammation – CBC, CRP, ESR, etc. However, medical providers don’t typically test patients unless they show signs of associated inflammatory diseases, such as diabetes, obesity, heart disease, arthritis, etc. They may require additional diagnostic tools and specialized tests, including:

• Biopsy
• Image scanning (X-ray, CT scan, MRI, ultrasound, PET scan, etc.)
• Allergy testing
• Autoimmune disease testing

Acute vs. Chronic Inflammation Prevention

When possible, disease prevention is better than treatment. Acute and chronic inflammation prevention techniques differ to some extent because their functions and causes vary.

Acute Inflammation

Acute inflammation is essential in helping the body cope with infection and injury. Instead of preventing it, focus on preventing its causes – injury, infection, and harsh chemicals. Avoid elements that hinder recovery and prolong the inflammatory response, such as alcohol, nicotine, unhealthy foods, and stress.

Chronic Inflammation

The best way to prevent chronic inflammation is to focus on eliminating unhealthy foods, maintaining a healthy weight, increasing physical activity, getting enough sleep, and limiting stress.

Acute vs. Chronic Inflammation Treatment

Inflammation requires medical attention and lifestyle modification.

Acute Inflammation

The treatment of acute inflammation depends on its cause. In case of bacterial infections, doctors prescribe antibiotics. Aspirin and non-steroidal anti-inflammatory agents are used for viral infections, fever, and pain. Corticosteroids, pain relievers, and cold compresses help with swelling and pain. Doctors also advise patients to eat healthfully, stay away from nicotine and alcohol, and rest.

Chronic Inflammation

Chronic inflammation requires a sustainable lifestyle modification, including:

• Improved diet – Limit or eliminate simple and added sugars, refined carbs, processed meat, saturated and trans fats, sports drinks, and other nutritionally-poor products. Eat more anti-inflammatory foods, including leafy greens, berries, tomatoes, onions, salmon and nuts; and add spices (curcumin, ginger, garlic, black pepper, etc.).
• Daily exercise – Even 20-30 minutes of regular, moderate physical activity improves inflammatory markers.
• Enough sleep – Seven to nine hours of uninterrupted sleep at night balances hormones and reduces inflammation.
• Reduced stress – Stress-relieving activities and hobbies lower cortisol levels, balance hormones, and decrease inflammation.
• Eliminating nicotine – Smoking promotes inflammation and is associated with various inflammatory diseases. Doctors recommend eliminating it altogether.
• Supplements – Health experts recommend taking natural supplements with proven anti-inflammatory properties, including vitamin C, vitamin D, glutathione, omega-3 fatty acids, zinc, selenium, iron, chromium, probiotics, etc.

Note: Read our article on how to reduce inflammation for more helpful tips and advice.

How Long Do Acute and Chronic Inflammation Last?

Acute inflammation starts immediately upon assault (injury, infection) and typically lasts several hours or days.

Chronic inflammation lasts much longer – from several months to several years, and in the case of some inflammatory diseases, it is life-long.

Consequences of Untreated Acute and Chronic Inflammation

Unresolved acute inflammation can turn into a chronic condition.

Untreated chronic inflammation can lead to more severe (in some cases, life-threatening) diseases, including premature skin aging, sexual dysfunction, diabetes, rheumatoid arthritis, neurodegenerative conditions, heart disease, and even cancer.

Conclusion

Inflammation is a vital defense mechanism that protects us from injury and infection. However, when it fails to eliminate the invading element, it turns into chronic inflammation that gradually destroys our tissues and organs.

Prevent chronic inflammation and reduce the risk of developing a severe inflammatory disease.