What is inflammation?

Michael B. Finkelstein, MD
Internal Medicine
Inflammation is a two-step process: First, extra blood flows to the site of injury and provides a cushioning layer of fluid, to prevent further exacerbation of that injury. Second, a particular set of molecules circulate around the site of injury, cleaning up the damaged tissue and replacing it with new tissue. If you think about watching a cut on your arm or leg during the healing process, you may recall seeing it get red and swollen initially, then begin to cover itself over with smooth new skin. That’s the inflammation process in action.

While a normal inflammatory response to occasional injury in the body is useful, a chronic inflammation in response to chronic injury is harmful.

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Anthony L. Komaroff, MD
Internal Medicine
Inflammation, the buildup of fluid and cells at the point of infection, is put into motion by cytokines -- proteins that are released into the blood by the innate immune system when it encounters germs. Cytokines function like police dispatchers. They signal there's a problem, which activates the immune system's highway patrol force: the circulating lymphocytes of the adaptive immune system. These lymphocytes cruise the highways of the blood vessels and lymphatic system. In response to the chemical signal from the cytokines, increased blood flow rushes these circulating cells to the trouble spot. The unpleasant heat, pain, redness, and swelling you feel are indications that help is on its way. As long as it's not overly prolonged, inflammation is a good thing. But if an inflammatory reaction goes on too long, the reaction itself becomes a problem.
Inflammation is your body’s reaction to injury, infection, or irritation. Anyone who’s ever had a mosquito bite has seen inflammation in action. It’s the swelling, redness, heat, and pain where the mosquito has bitten you. And if you’re the type to scratch your mosquito bites, you know something else about inflammation: it tends to get worse quickly if you irritate the affected area.
Grant Cooper, MD
Physical Medicine & Rehabilitation
Inflammation is a complex biological response by the body to harmful stimuli, including bacteria, viruses, fungus, irritants, and physical injury. Chronic inflammation can lead to a number of diseases, including arthritis.
The Arthritis Handbook: Improve Your Health and Manage the Pain of Osteoarthritis (A DiaMedica Guide to Optimum Wellness)

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The Arthritis Handbook: Improve Your Health and Manage the Pain of Osteoarthritis (A DiaMedica Guide to Optimum Wellness)

According to conventional wisdom, arthritis pain is an inevitable part of aging. Not so, says Dr. Grant Cooper in this practical, accessible guide. For those who do develop osteoarthritic conditions,...

Inflammation is your body's natural response to destroy or get rid of dangerous substances like allergens or bacteria. Sometimes, however, your body attacks itself, leading to different parts of your body becoming inflamed. This can affect your organs and bones and cause pain, swelling, and redness.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.