Inflammation is a mechanism of innate immunity and is one of the many ways in which the body knows how to protect itself. It is marked by redness, swelling, heat, pain, and occasionally loss of function in a localized area. When inflammation occurs, it means that white blood cells are releasing chemicals into the blood, trying to get rid of harmful substances that have invaded the body. This increases blood flow to the affected area, causing redness and warmth. When the chemicals released by the white blood cells get into the surrounding tissue, it causes swelling which triggers the nerves and results in pain.
The immune cells go to work eliminating the cause of cell injury and trying to limit tissue damage and begin tissue repair.
Sometimes the body’s defense mechanism triggers inflammation when there are no foreign bodies to fight off. This is what happens with autoimmune diseases such as arthritis. Arthritis is a general term for inflammation of the joints that is not connected with fighting off harmful invaders. This chronic inflammation is extremely painful and causes joint stiffness, pain, and loss of function in the joints.