Pain in spondyloarthritis: A neuro-immune interaction.

Pain in spondyloarthritis is usually attributed to inflammation. However, treatment with potent biologic agents that control inflammation does not always control the pain. Pain is hence likely to be multifactorial. Fatigue is another prominent feature of this condition which again tends to respond poorly to potent biologic agents. There is also a growing interest in coexisting fibromyalgia in this group of patients and how this affects response to biologic therapies. Advances in neuroimaging have helped in better understanding the dynamic nature of brain networks in the perception of pain. Animal models have helped in developing concepts of peripheral and central sensitization in pain transmission. This review discusses the neuroimmune basis of pain in ankylosing spondylitis, with an emphasis on brain networks and the complex interactions between the nervous system and the immune system at various levels. It also provides some insights into the differences in pain perception between men and women.