All about inflammation

By , Former Executive Editor, Harvard Women's Health Watch

Anyone who has ever sprained their ankle, cut themselves while chopping vegetables, or been stung by a bee has seen the effects of inflammation firsthand. The pain, redness, swelling, and heat that it produces is the body's defense mechanism to fight off infectious agents like bacteria and repair tissue damage. Less obvious, but similar in process, is the inflammation that results from an infection like a cold, the flu, or COVID-19.

Acute vs. chronic inflammation

Injuries and infections produce acute inflammation, the body's rapid response mechanism that aims to rid itself of the dangerous invader and return it to a state of balance. A release of warning chemicals sounds the alarm, which draws an army of white blood cells to the site of injury. Some of these cells neutralize the invaders, while others clean up the damage that results from the battle. Acute inflammation typically resolves quickly, within a period of hours to days.

Chronic inflammation can begin via the same process, with the body trying to rid itself of what the immune system interprets as foreign adversaries. But this can become a persistent state, even if the perceived threat isn't truly harmful to one's health. In autoimmune disorders like rheumatoid arthritis, lupus, type 1 diabetes, ulcerative colitis, and multiple sclerosis, the body mistakenly reacts to its own tissues as if they were foreign, and produces damaging inflammation against them.

This chronic kind of low-grade inflammation may continually simmer under the surface. An unhealthy lifestyle that includes smoking, a poor diet, alcohol consumption, sedentary behavior, stress, and weight gain can cause this type of persistent inflammation.

Symptoms of inflammation

Acute inflammation produces very obvious and immediate symptoms such as:

  • Redness
  • Pain
  • Warmth
  • Swelling

Chronic inflammation is a more gradual and subtle process. When symptoms do appear, they can include:

  • Fatigue
  • Muscle aches and joint pain
  • Constipation, diarrhea, and other gastrointestinal issues
  • Weight gain
  • Headaches
  • Skin rashes

Unlike with acute inflammation, these symptoms continue long-term or come and go over time.

Diseases linked to chronic inflammation

Inflammation and the harmful chemicals it produces can contribute to all of the following conditions:

  • Alzheimer's and other forms of dementia
  • Cancer
  • Anxiety and depression
  • High blood pressure, heart disease, and stroke
  • Type 2 diabetes
  • Allergies and asthma
  • Skin conditions like acne, eczema, and psoriasis
  • Arthritis

Treating inflammatory diseases

Medical treatments for well-defined inflammatory conditions, such as rheumatoid arthritis and inflammatory bowel disease, work by dampening the overactive immune response either locally, or throughout the body. Examples include:

  • Corticosteroids. These drugs are designed to mimic the effects of cortisol, a powerful natural anti-inflammatory hormone the adrenal glands produce. Corticosteroids act directly on inflammatory cells throughout the body to treat conditions like rheumatoid arthritis and asthma.
  • Immunosuppressant medications. Methotrexate and other drugs within this group also dampen the immune system response. Doctors prescribe them to treat conditions like eczema and rheumatoid arthritis.
  • Biologics. This class of drugs is made from living organisms, which are genetically engineered to target specific cells or proteins that control the inflammatory process in diseases like asthma, psoriasis, and multiple sclerosis.

But for chronic low grade inflammation not caused by a defined illness, lifestyle changes are the mainstay of both prevention and treatment.

Preventing inflammation

Here are a few strategies to combat inflammation and its many damaging effects on the body:

  • Eat an anti-inflammatory diet that includes primarily fruits, vegetables, nuts, whole grains, fatty fish (salmon, sardines, tuna), and healthy oils. Limit foods that are high in simple sugars (sodas, candy) and refined carbohydrates (cookies, pie). The Mediterranean diet encompasses many of these principles.
  • Try to do at least 150 minutes of aerobic exercise, plus two or more strength training sessions, each week.
  • Manage weight with diet and exercise.
  • Sleep for at least seven to nine hours nightly.
  • Quit smoking and limit alcohol to one or two drinks each day.
  • Reduce chronic stress by engaging in relaxing activities such as deep breathing, meditation, and yoga.

Image: NickyLord/Getty Images

About the Author

photo of Stephanie Watson

Stephanie Watson, Former Executive Editor, Harvard Women's Health Watch

Stephanie Watson was the Executive Editor of the Harvard Women’s Health Watch from June 2012 to August 2014. Prior to that, she worked as a writer and editor for several leading consumer health publications, including WebMD, … See Full Bio
View all posts by Stephanie Watson


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