There are many reasons that patients may develop neuropathic pain. However, on a cellular level, one explanation is that an increased release of certain neurotransmitters which signal pain, combined with an impaired ability of the nerves to regulate these signals leads to the sensation of pain originating from the affected region. Additionally, in the spinal cord, the area which interprets painful signals is rearranged, with corresponding changes in neurotransmitters and loss of normally-functioning cell bodies; these alterations result in the perception of pain even in the absence of external stimulation. In the brain, the ability to block pain can be lost following an injury such as stroke or trauma. Over time, further cellular damage occurs and the sense of pain persists.
Neuropathic pain is associated with diabetes, chronic alcohol intake, certain cancers, vitamin B deficiency, infections, other nerve-related diseases, toxins, and certain drugs.