Inflammation can affect any part of the body.
When something harmful or irritating affects a part of our body, there is a biological response to try to remove it, the signs and symptoms of inflammation show that the body is trying to heal itself.
Inflammation does not necessarily mean that there is an infection, but an infection can cause inflammation. Infection can be caused by bacteria, viruses, or fungi, and inflammation is the body's response to it.
Contents of this article:
- What is inflammation?
- Inflammation helps wounds heal
- Inflammation is part of our innate immunity
- What is the difference between chronic inflammation and acute inflammation?
- What happens during acute inflammation?
- Acute and chronic inflammation compared
- Why does inflammation cause pain?
- Autoimmune disorders and inflammation
- Treatments for inflammation
- Some herbs have anti-inflammatory properties
- Inflammation is the body's attempt at self-protection to remove harmful stimuli and begin the healing process.
- Inflammation is part of the body's immune response.
- Infections, wounds, and any damage to tissue would not be able to heal without an inflammatory response.
- Chronic inflammation can eventually cause several diseases and conditions, including some cancers and rheumatoid arthritis.
What is inflammation?
Inflammation is part of the body's immune response. Initially, it can be beneficial when, for example, your knee sustains a blow and tissues need care and protection. However, sometimes, inflammation can persist longer than necessary, causing more harm than benefit.
Inflammation helps wounds heal
Our immediate reaction to a swelling is to try and decrease it. However, it is important to remember that inflammation is an essential part of the body's attempt to heal itself.
The first stage of inflammation is often called irritation, which then becomes inflammation - the immediate healing process. Inflammation is followed by suppuration (discharging of pus). Then there is the granulation stage, the formation of new tissue in a wound during healing. Inflammation is part of a complex biological response to harmful stimuli. Without inflammation, infections and wounds would never heal.
Inflammation is part of our innate immunity
Our innate immunity is naturally present in our bodies when we are born. This is different from adaptive immunity, which we develop after an infection or vaccination, when the body "learns" to fight a specific pathogen.
Innate immunity is generally nonspecific, while adaptive immunity is specific to a particular pathogen:
The difference between chronic inflammation and acute inflammation
Acute inflammation - starts rapidly (rapid onset) and quickly becomes severe. Signs and symptoms are only present for a few days, but, in some cases, may persist for a few weeks.
Examples of diseases, conditions, and situations that can result in acute inflammation include:
- acute bronchitis
- infected ingrown toenail
- sore throat from a cold or flu
- a scratch or cut on the skin
- exercise (especially intense training)
- acute appendicitis
- acute dermatitis
- acute tonsillitis
- acute infective meningitis
- acute sinusitis
- a blow
Chronic inflammation - this means long-term inflammation and can last for several months and even years. It can result from:
- Failure to eliminate whatever was causing an acute inflammation.
- An autoimmune response to a self-antigen - the immune system attacks normal healthy tissue, mistaking it for harmful pathogens.
- Exposure to a low level of a particular irritant, such as a chemical, over a long period.
Examples of diseases and conditions that include chronic inflammation:
Rheumatoid arthritis involves chronic inflammation.
- chronic peptic ulcer
- rheumatoid arthritis
- chronic periodontitis
- ulcerative colitis and Crohn's disease
- chronic sinusitis
- chronic active hepatitis (there are many more)
Although damaged tissue cannot heal without inflammation, chronic inflammation can eventually cause several diseases and conditions including some cancers, rheumatoid arthritis, atherosclerosis, periodontitis, and hay fever. Inflammation needs to be well regulated.
What happens during acute inflammation?
Within a few seconds or minutes after tissue is injured (physical injury, infection, or an immune response), acute inflammation starts to occur. Three main processes occur before and during acute inflammation:
1) Arterioles - small branches of arteries that lead to the capillaries that supply blood to the damaged region dilate, resulting in increased blood flow.
2) Capillaries - become more permeable so fluid and proteins can move between blood and cells (interstitial spaces).
3) Neutrophils - (a type of white blood cell) move out of capillaries and venules (small veins that go from a capillary to a vein) and move into interstitial spaces. Neutrophils are filled with tiny sacs, which contain enzymes that digest microorganisms.
When our skin is scratched (and the skin is not broken), one may see a pale red line. Soon, the area around the scratch goes red; this is because blood vessels have dilated and capillaries have filled up with blood, becoming more permeable, which allows fluid and blood proteins to move into the space between tissues.
Edema - the area then swells as more fluid builds up in the interstitial spaces.
The five major signs of acute inflammation - "PRISH"
- Pain - the inflamed area is likely to be painful, especially when touched. Chemicals that stimulate nerve endings are released, making the area much more sensitive.
- Redness - this is because the capillaries are filled up with more blood than usual.
- Immobility - there may be some loss of function.
- Swelling - caused by an accumulation of fluid.
- Heat - more blood in the affected area makes it feel hot to the touch.
These five acute inflammation signs are only relevant when the affected area is on or very close to the skin. When inflammation occurs deep inside the body, such as an internal organ, only some of the signs may be detectable.
Some internal organs may not have sensory nerve endings nearby, so there will be no pain, as is the case with some types of pneumonia (acute inflammation of the lung). If the inflammation from pneumonia pushes against the inner lining of the chest wall, then there may be pain.
Acute and chronic inflammation compared
The lists below show the major differences between chronic and acute inflammation:
- Caused by - harmful bacteria or injury to tissue.
- Major cells involved - mainly neutrophils, basophils (in the inflammatory response), and eosinophils (response to parasites and worms), and mononuclear cells (macrophages, monocytes).
- Onset (when does the inflammation start) - rapid.
- Duration - short-lived, generally a few days.
- Outcomes - the inflammation gets better, develops into an abscess, or persists as chronic inflammation.
- Caused by - non-degradable pathogens that cause persistent inflammation, infection with some types of viruses, persistent foreign bodies, overactive immune system reactions.
- Major cells involved - Macrophages, lymphocytes, plasma cells, and fibroblasts.
- Duration - from several months to years.
- Outcomes - the destruction of tissue, thickening, and scarring of connective tissue (fibrosis), death of cells or tissues (necrosis).
Why does inflammation cause pain?
When people have inflammation, it often hurts. They feel pain, stiffness, discomfort, distress, and even agony, depending on the severity. The type of pain varies. It can be a constant and steady ache; a throbbing, pulsating pain; a stabbing; or a pinching pain.
Inflammation primarily causes pain because the swelling pushes against the sensitive nerve endings, which send pain signals to the brain. Nerve endings send pain signals to the brain all day long; however, it learns to ignore most of them, unless pressure against the nerve endings increases.
Other biochemical processes also occur during inflammation that affect how nerves behave and cause pain.
Autoimmune disorders and inflammation
An autoimmune disease is one where the immune system attacks healthy tissues, mistaking them for harmful pathogens or irritants. This immune response triggers an inflammatory response.
There are hundreds of autoimmune diseases, and nearly all of them have inflammation as one of the signs, examples include:
Rheumatoid arthritis - inflammation in the joints, tissues surrounding the joints, and sometimes other organs in the body.
Ankylosing spondylitis - inflammation of the vertebrae, muscles, ligaments, and also the sacroiliac joints (where the spine and hips meet).
Celiac disease - inflammation and destruction of the inner lining of the small intestine.
Crohn's disease - the gastrointestinal (GI) tract becomes inflamed. Inflammation is most common in the ileum (small intestine) but may occur anywhere in the GI tract, from the mouth to the anus.
Idiopathic pulmonary fibrosis - inflammation within the alveoli (tiny sacs within the lungs).
Lupus - there can be inflammation of the joints, lungs, heart, kidney, and/or skin.
Psoriasis - inflammation of the skin. In some cases, as in psoriatic arthritis, the joints and tissue surrounding the joints may also become inflamed.
Type 1 diabetes - inflammation in various parts of the body are likely if the condition is not well controlled.
Addison's disease - primarily inflammation of the adrenal glands.
Various allergies - all allergies have inflammation. Asthma has inflammation of the airways; in hay fever, the nose, ear, and throat mucous membranes become inflamed. People who are allergic to bee stings may develop serious, life-threatening inflammation that affects the whole body (anaphylaxis).
The disorders above are just a few examples of the hundreds of autoimmune disorders that include inflammation.
Treatments for inflammation
As mentioned earlier in this article, inflammation is part of the healing process. Sometimes, reducing inflammation is helpful, though not always necessary.
NSAIDs (non-steroidal anti-inflammatory drugs) are taken to alleviate pain caused by inflammation. They counteract an enzyme called COX (cyclooxygenase), which normally makes prostaglandins, which create inflammation. If prostaglandin synthesis can be blocked, pain is either removed or reduced.
NSAIDs include naproxen, ibuprofen, and aspirin.
People should not use NSAIDs long-term without asking a doctor because there is a risk of developing stomach ulcers, which can result in severe, life-threatening bleeding. NSAIDs may also worsen asthma symptoms and cause kidney damage. NSAID medications, except aspirin, can also increase the risk of stroke and myocardial infarction (heart attack).
Acetaminophen (paracetamol, Tylenol) can reduce pain associated with inflammatory conditions without reducing inflammation. They may be ideal for those wishing to treat just the pain while allowing the inflammation to run its course.
Corticosteroids - these are a class of steroid hormones naturally produced in the cortex (outer portion) of the adrenal gland. They are synthesized in laboratories and added to medications.
Corticosteroids, such as cortisol are anti-inflammatory; they prevent a number of mechanisms involved in inflammation.
There are two sets of corticosteroids:
Glucocorticoids - prescribed for inflammation of the joints (arthritis), temporal arteritis, dermatitis, inflammatory bowel disease, systemic lupus, hepatitis, asthma, allergic reactions, and sarcoidosis. Creams and ointments may be prescribed for inflammation of the skin, eyes, lungs, bowels, and nose.
Mineralocorticoids - used to treat cerebral salt wasting, and to replace missing aldosterone (a hormone) for patients with adrenal insufficiency.
Corticosteroid side effects are more likely if taken in oral form, compared with inhalers or injections. The higher the dosage and/or the longer they are taken, the greater the risk of side effects.
Inhaled medications, such as those used to treat asthma over the long-term raise the risk of developing oral thrush. Rinsing the mouth out with water after each use can help prevent oral thrush.
Glucocorticoids can also induce Cushing's syndrome, while mineralocorticoids can cause high blood pressure (hypertension), low blood potassium levels (hypokalemia), connective tissue weakness, and metabolic alkalosis.
Some herbs have anti-inflammatory properties
Use of herbal supplements should be discussed with a doctor.
Harpagophytum procumbens - also known as devil's claw, wood spider, or grapple plant comes from South Africa and is related to sesame plants. Some research has shown it may have anti-inflammatory properties.
Hyssop Hyssopus - from the plant family Lamiaceae is mixed with other herbs, such as licorice for the treatment of some lung conditions, including inflammation. Beware of the essential oils of hyssop, as they can lead to life-threatening convulsions in laboratory animals.
Ginger - has been used for hundreds of years to treat dyspepsia, constipation, colic, other gastrointestinal problems, as well as rheumatoid arthritis pain.
Turmeric (Curcuma longa) - also a plant of the ginger family. Current research is looking into the possible beneficial effects of turmeric in treating arthritis, Alzheimer's disease, and some other inflammatory conditions. Curcumin, a substance found in turmeric, is under investigation for the treatment of several illnesses and disorders, including inflammation.
Cannabis - contains a cannabinoid called cannabichromene, which has been shown to have anti-inflammatory properties.