Central Sensitivity Syndrome: Treatment and Symptoms

Central sensitization syndromes (CSS) are a collection of disorders where the central nervous system misfires and amplifies sensory input resulting in pain, fatigue, brain fog, and sleep problems. Fibromyalgia (FMS), chronic fatigue syndrome (ME/CFS), and other chronic pain conditions fall under the CSS description.

Central sensitization syndromes are sometimes known as functional disorders, unexplained symptoms, or somatic symptom disorder. Pain is a shared symptom, but fibromyalgia, chronic fatigue, and other central sensitization syndromes have a broad range of physical and psychological symptoms that span multiple systems and can be hard to classify.

This article discusses central sensitization syndromes, what's known about the underlying mechanisms behind CSS, and available treatment options.

What Is a Central Sensitization 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.

In CSS, the body becomes sensitive to things that are processed by the central nervous system. Allodynia—pain due to a stimulus that does not typically provoke it, like a hug—results in episodes where certain things cause pain where none existed before.

A development called global sensory hyperresponsiveness can mean that bright lights, loud noises, strong smells, or certain foods or chemicals cause a strong response. This is a common symptom for people with fibromyalgia.

Types of Central Sensitization Syndrome

Fibromyalgia is considered a central sensitization syndrome, but a number of health conditions also may be considered in the CSS category. These conditions include:

• 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)

Mental health disorders are common in CSS as well. Some researchers suggest the conditions all involve dysregulation of the same neurotransmitters (chemical messengers), 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

What Are the Symptoms of Central Sensitization Syndrome?

Neurotransmitters that are involved in at least some of the CSS include:

• Serotonin
• Norepinephrine
• Dopamine
• GABA and 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 feel like your clothes painful even when they're not too tight, or make you unable to enjoy touch. 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 Sensitization Syndromes

The different individual symptoms and mechanisms of each CSS require a customized treatment approach, but in general, most CSSs tend to respond to some of the same types of treatment. They can include 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 healthcare provider about any symptoms that don't seem to be related to your current diagnoses.

Summary

Central sensitization syndromes involve a group of different conditions that share pain symptoms and patterns, including fibromyalgia and chronic fatigue syndrome. CSS symptoms also include a strong response to environmental stimuli and are frequently present alongside certain mental health conditions.

Treatment can include interventions for specific physical symptoms, as well as cognitive behavioral therapy and antidepressant medication. Talk to your healthcare provider if you have symptoms of pain, fatigue, allodynia, or specific signs of a condition like irritable bowel syndrome.