What is inflammatory pain?

Inflammatory pain is defined as increased sensitivity due to the inflammatory response associated with tissue damage.⁵ It is characterized by the perception of, and affective response to, noxious stimuli that occur during an inflammatory or immune response.¹⁰Vasko M.R. (2009) Inflammatory Pain. In: Binder M.D., Hirokawa N., Windhorst U. (eds) Encyclopedia of Neuroscience. Springer, Berlin, Heidelberg. https://link.springer.com/referenceworkentry/10.1007%2F978-3-540-29678-22436. Accessed Feb 14, 2020

Symptoms of inflammatory pain

Inflammatory Pain is characterized by five classic symptoms: redness (rubor), heat (calor), swelling (tumor), pain or hypersensitivity (dolor), and loss of function (functio lasea).¹¹Vasko M.R. (2009) Inflammatory Pain. In: Binder M.D., Hirokawa N., Windhorst U. (eds) Encyclopedia of Neuroscience. Springer, Berlin, Heidelberg. https://link.springer.com/referenceworkentry/10.1007%2F978-3-540-29678-22436. Accessed Feb 14, 2020

What causes inflammatory pain?

Inflammation and reparatory processes take place after an injury. These processes can lead to a hyperexcitable state known as peripheral sensitization. Inflammatory mediators released from nociceptive terminals increase vascular permeability, leading to localized edema and the escape of the by-products of injury, such as prostaglandins, bradykinin, growth factors, and cytokines. These substances can sensitize, as well as excite, nociceptors, resulting in lowered firing thresholds and ectopic discharges. In most patients this state resolves as healing occurs and inflammation subsides. However, these analgesic agents lower the activation threshold and can change the properties of the primary sensory neurons surrounding the area of trauma, causing a sensation of pain in areas adjacent to those of the actual injury.¹²Cohen SP, Mao J. Neuropathic pain: mechanisms and their clinical implications. BMJ. 2014 Feb 5; 348:f7656, p3