Derek Burnett
Derek Burnett is a Contributing Writer at Bottom Line Personal, where he writes frequently on health and wellness. He is also a contributing editor with Reader’s Digest magazine.
The more we learn about chronic inflammation, the more we understand just how deeply it is implicated in an enormous variety of diseases and conditions. Whether the problem is located in the brain, the skin, lungs/allergies, or the digestive system, long-term, low-level inflammation appears to be a frequent factor.
Researchers are still sharpening their understanding of the role of inflammation in disease. For many of these illnesses and conditions, we know that chronic inflammation is present, but is it a direct cause? Is it a contributing cause along with other factors? Is it an effect of the disease? Or could it possibly be all of the above? We don’t know yet, but what we can say with certainty is that chronic inflammation is associated with the following conditions.
An allergy is an overactive immune response to an innocuous environmental stimulus that the immune system incorrectly sees as a danger. For example, tree pollen is not inherently harmful to human health. Someone without an allergy can therefore be exposed to pollen without an issue, while a person with a pollen allergy will suffer. When an allergic person encounters such a substance, their immune system releases several inflammation-producing chemicals such as histamines and prostaglandins which prompt the symptoms we usually associate with allergies, including teary eyes, runny nose, reddened skin, swollen tissues, coughing, itching, and wheezing. If the allergic person is exposed to the allergen continuously or repeatedly, the persistent inflammation can cause permanent changes to the affected organs.
Some people’s asthma is caused by allergies, while others might experience flare-ups from exposure to viruses, from exercise, or from irritants such as wood smoke. In allergic asthma, allergens trigger an overactive immune response, with the principal effects felt in the airway system. But low-level inflammation is constantly present in people with non-allergic asthma, which causes thickening and scarring in the bronchial tubes.
The telltale itchy skin rash associated with eczema is the result of an overzealous immune response in which the body releases inflammatory cells. When people with eczema scratch at their rash, it becomes even more inflamed, which can result in a vicious cycle of chronic inflammation even when there is no outbreak. Unfortunately, this constant low level of inflammation is associated with increased risk of heart disease and stroke.
Inflammatory Bowel Disease (IBD) is an umbrella term covering two autoimmune diseases affecting the digestive system: Crohn’s Disease and ulcerative colitis. It should not be confused with Irritable Bowel Syndrome (IBS), which occurs without inflammation. Crohn’s and ulcerative colitis are very similar conditions in which parts of the digestive tract are inflamed and prone to ulcers. With Crohn’s, the tissue damage can occur anywhere in the digestive system, while in ulcerative colitis it is limited to the bowel and rectum. IBD often runs in families. Whatever its cause, the condition is marked by an abnormal immune response to gut bacteria which drives inflammation. Over time, the chronic inflammation caused by IBD can increase the risk of colorectal cancer.
Lupus is an autoimmune disease that can affect organs throughout the body…the skin, the eyes, the joints, the brain, the muscles, the digestive system, the lungs, and more. Which body parts will be affected appears unpredictable and idiosyncratic. A key feature of the disease is that the body struggles to clear away dead or damaged cells, allowing biological debris to pile up, which the body’s immune system attacks. Unfortunately, this constant state of immune response means that healthy tissue is also persistently exposed to inflammation, which causes accumulating damage over the long term.
Multiple sclerosis (MS) is an autoimmune disorder in which the body directs an inflammatory immune attack against its own healthy tissue…specifically, the sheath known as myelin that protects and insulates nerve fibers. In the progressive form of the disease, the patient may develop neurological symptoms including difficulty walking, weakness, impaired vision, incontinence, and muscle spasms.
In rheumatoid arthritis (RA), an abnormal immune response causes inflammation in the synovium, which is the tissue surrounding the joints. The inflammatory chemicals released by the immune system may not only destroy the joints but go on to damage cartilage, ligaments, tendons and bone…and, later, the skin, lungs, blood vessels, and eyes.
In this autoimmune condition, the body produces new skin cells faster than it can dispose of the old ones, causing them to pile up on the skin’s surface. The immune system then attacks the excess cells, with the resulting inflammation causing the formation of red, scaly plaques on the elbows, knees, or scalp. In some people with skin psoriasis, the joints also become affected, a condition known as psoriatic arthritis.
Age-Related Macular Degeneration (AMD) is the leading cause of vision loss, which occurs when a part of the retina called the macula, which houses light-sensing cells, becomes damaged. Inflammation is implicated in both of its two types, wet AMD and dry AMD. Infections, or a lifetime of cell damage caused by smoking or other factors, can cause inflammation in the cells of the eyes. As we age, it becomes more difficult for our bodies to combat inflammation, especially when the inflammation is overactive or chronic, as may be the case with AMD. In dry AMD, bits of dead or damaged rod and cone cells accumulate in the retina, disrupting eyesight at the center of vision, while the blood vessels at the back of the eye begin to fail. Wet AMD is the more advanced stage of the disease, which happens when an inflammatory response to this state causes the growth of abnormal blood vessels in the macula, which leak blood or other fluids, causing serious damage to the organ.
Most people are aware that Alzheimer’s dementia is marked by the presence of amyloid plaques and tau tangles, which unsurprisingly are often accompanied by inflammation. But researchers are now exploring the nature of inflammation’s role in the disease. Rather than inflammation being caused by the plaques and tangles, the causality could be reversed, with chronic inflammation triggering the formation of these harmful proteins.
People with Parkinson’s disease have been shown to have significantly elevated markers of inflammation in their brains, blood, and cerebrospinal fluid. And higher levels of inflammation were linked to worse cognitive scores. However, as with Alzheimer’s disease, it’s not yet clear whether inflammation causes the disease or is a symptom of it.
Medical researchers once considered atherosclerosis to consist merely of the buildup of fats in the arterial walls. Today, the disease is widely understood to be a chronic inflammatory disease. In other words, the problem is not just that plaques form on the walls of arteries, but that the immune system responds by walling off the plaque, making it larger and thus potentially more obstructive to blood flow, or causing it to rupture, triggering a life-threatening blood clot.
