CFS & Fibromyalgia Related Conditions Central Sensitivity Syndromes By Adrienne Dellwo linkedin Adrienne Dellwo is an experienced journalist who was diagnosed with fibromyalgia and has written extensively on the topic. Learn about our editorial process Adrienne Dellwo Medically reviewed by Medically reviewed by Grant Hughes, MD on January 18, 2020 linkedin Grant Hughes, MD, is board-certified in rheumatology and is the head of rheumatology at Seattle's Harborview Medical Center. Learn about our Medical Review Board Grant Hughes, MD Updated on January 01, 2021 Print Fibromyalgia (FMS) and chronic fatigue syndrome (ME/CFS) are difficult illnesses to classify. Both have a broad range of physical symptoms that span multiple systems, and they're associated with multiple psychological symptoms as well. In addition, they're often accompanied by a slew of other illnesses — many of which are also hard to classify. As scientists are getting more of a handle on FMS, ME/CFS and other related illness, an umbrella term that's more frequently used to describe them is central sensitivity syndromes or CSS. Some researchers argue that this term should replace other terms, such as functional somatic syndrome, medically unexplained syndrome, and somatoform disorders because they believe CSS is more accurate. Westend61 / Getty Images What Is a Central Sensitivity Syndrome? An illness described as a CSS involves something called central sensitization. "Central" means the central nervous system, which is made up of your brain and spinal cord. "Sensitization" is the end result of something that has made you sensitive. Allergies are the type of sensitivity people are generally the most familiar with. In allergies, your body has an inappropriate physical reaction to something that doesn't bother other people at all. In fact, while the sensitivities of a CSS aren't exactly allergies, they do involve an inappropriate physical reaction. In CSS, we become sensitive to things that are processed by the central nervous system, which can include bright lights, loud noises, strong smells, rough textures, and pressure on the body. It may also involve certain foods or chemicals. Especially in FMS, the body is sensitized to anything unpleasant, i.e., cold, heat, a tickle or an itch. Aside from FMS and ME/CFS, the following conditions have been proposed to be part of the CSS family: Chronic pelvic pain, including vulvodynia Headache and migraine Idiopathic low back pain Interstitial cystitis (painful bladder) Irritable bowel syndrome Multiple chemical sensitivity Myofascial pain syndrome Primary dysmenorrhea (painful period) Restless legs syndrome Temporomandibular joint disorder (TMJ) Psychiatric disorders are common in CSS as well. Research suggests that's because they all involve dysregulation of the same neurotransmitters, with the dysregulation in CSS in different regions of the brain than in psychiatric disorders. Psychiatric conditions that commonly overlap with CSS include: Major depression Obsessive-compulsive disorder Bipolar disorder Post-traumatic stress disorder Generalized anxiety disorder Panic attack Features of CSS Neurotransmitters that are involved in at least some of the CSS include: Serotonin Norepinephrine Dopamine GABA & glutamate The pain of CSS comes from a couple of different abnormal pain types: hyperalgesia and allodynia. Hyperalgesia takes normal pain from things that everyone considers painful (a broken limb, an infected tooth, etc.) and makes it worse. It's often referred to as "turning up the volume" of pain. This makes things like injuries, surgeries, and chronic sources of pain especially debilitating. Allodynia makes you feel pain from things that shouldn't hurt, such as the brush of fabric against your skin, or your arm resting against your side when you sleep. Allodynia can make your clothes painful even when they're not too tight, or make you unable to enjoy a hug. It turns all manner of ordinary experiences into painful ones, which often means making significant changes to your life to minimize it. Other proposed mechanisms of CSS include: Inflammation in or originating in the nervous system Autonomic nervous system dysfunction Dysfunction of the HPA axis, which is part of the body's stress-response system Treating Central Sensitivity Syndromes The different individual symptoms and mechanisms of each CSS require a customized treatment approach, but in general, most CSS tend to respond to some of the same types of treatment, especially antidepressants (which help correct neurotransmitter dysregulation), exercise, and cognitive-behavioral therapy (CBT). However, it should be noted that people with ME/CFS have special considerations when it comes to exercise, and CBT is a highly controversial treatment for this illness, especially when it's paired with graded exercise. While these conditions are believed to be related, it's important to get each one diagnosed and treated properly. Be sure to talk to your doctor about any symptoms that don't seem to be related to your current diagnoses. A Word From Verywell The CSS classification is good news for all of us with these conditions. It signifies a positive change in how these illnesses are understood and viewed by the medical community. That's what we need when it comes to getting research attention, which leads to better diagnostics and treatments. Was this page helpful? Thanks for your feedback! Learn about treatment and lifestyle changes to cope with fibromyalgia and chronic fatigue syndrome. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Mayer TG, Neblett R, Cohen H, et al. The development and psychometric validation of the central sensitization inventory. Pain Pract. 2012;12(4):276-285. doi:10.1111/j.1533-2500.2011.00493.x Yunus MB. The prevalence of fibromyalgia in other chronic pain conditions. Pain Res Treat. 2012;2012:584573. doi:10.1155/2012/584573 Adams LM, Turk DC. Psychosocial factors and central sensitivity syndromes. Curr Rheumatol Rev. 2015;11(2):96-108. Nijs J, Malfliet A, Ickmans K, Baert I, Meeus M. Treatment of central sensitization in patients with 'unexplained' chronic pain: an update. 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