Central sensitization syndrome: What to know

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Central sensitization is a syndrome, not a diagnosis. It means that the CNS intensifies nerve signals, causing a person to have more intense sensory experiences than usual. This often results in pain or other atypical or extreme sensations.

The pain may have associations with worsening anxiety and memory loss.

People with multiple chronic conditions may experience localized and centralization pain syndrome. Sometimes, as with rheumatoid arthritis (RA), people may experience central sensitization over time.

Central sensitization may occur indepenently or result from other syndromes, such as fibromyalgia. Or it may occur alongside injuries or illnesses, worsening the symptoms of those conditions.

Other names for central sensitization syndrome:

• central pain syndrome
• centralized pain
• widespread or diffuse pain

Chronic pain remains poorly understood. Doctors have not identified the cause of every chronic pain condition or named every source of chronic pain. So the role of central sensitization in various disorders is unclear, and the research is ongoing.

However, most researchers agree that central sensitization plays a role in many pain disorders, especially when doctors can find no physical cause of the pain. Some unexplained types of pain that may suggest a person has central sensitization include:

• chronic stomach pain, diarrhea, or constipation
• pelvic or sexual pain
• headaches
• dizziness
• interstitial cystitis
• ringing ears
• chronic muscle or joint pain

Illness or injury can cause these symptoms, but sometimes central sensitization is responsible.

Central sensitization may also intensify the pain of chronic conditions, such as rheumatoid arthritis, and injuries, such as sprains, strains, and broken bones.

Also, research shows that central sensitization plays an important role in fibromyalgia. Fibromyalgia is a condition affecting the entire body, causing pain and tenderness. It may also lead to sleeping issues or fatigue.

Researchers do not fully understand what causes central sensitization. Some theories they propose include the following:

• Neuroinflammation: This type of inflammation in the brain and spinal cord may change how the nervous system processes pain. Many traumatic conditions can trigger neuroinflammation, for example, brain injury, certain medications, and other medical conditions.
• Injuries: When body tissue suffers an injury, it typically releases inflammatory chemicals to aid healing. This process may sensitize neurons (nerve cells), causing a person to feel pain even after the injury heals.
• Psychological factors: Pain is an emotional and physical experience. How people feel and speak about their pain may alter how their brain perceives it.

Risk factors

Certain factors may increase the likelihood of developing central sensitization, such as:

• having a chronic pain condition, such as arthritis
• some autoimmune conditions, where the body’s immune system attacks its own cells
• a family history of the condition since central sensitization has some genetic links
• triggering events in the environment, such as infections or injuries
• having a family history of mood disorders

The main symptom of central sensitization syndrome is chronic pain that either has no clear physical cause or is disproportionate to its physical cause.

For example, a person might complain of widespread muscle and joint pain but not have any obvious injuries or diseases. Or they might say that a minor injury causes unbearable pain.

Some hallmarks of central sensitization include:

• having pain that a doctor cannot diagnose the cause of
• ongoing chronic pain that does not respond to physical treatment
• being highly sensitive to pain

Central sensitization is a hypothesis for explaining several different chronic pain syndromes, not a formal medical diagnosis. Currently, no test can conclusively determine that a person has this condition.

Instead, a doctor usually rules out other causes by checking for muscle, joint, or bone injuries with imaging tests, such as X-rays.

A healthcare professional may also do bloodwork to look for infections or illnesses that may cause chronic pain, such as rheumatoid arthritis.

After ruling out other conditions, a doctor may ask questions about medical history, such as the type and severity of pain a person is experiencing. They may also do tests for sensitization, such as testing what kind of reaction a mildly painful stimulus elicits.

Doctors may find it challenging to treat central sensitization syndrome and may not provide a person with a specific diagnosis. Some people may mistakenly believe that doctors have told them their pain is all in their heads or made up. So they may resist trying treatments that act on the brain and the emotions of pain.

Some treatments, such as antidepressants and certain antiepileptic medications, can help with the symptoms. They may work by altering chemicals in the brain that mediate pain.

Other methods include:

• treating any underlying medical condition, such as a chronic injury or opioid abuse
• therapy, especially cognitive behavioral therapy (CBT), to deal with the emotional aspects of living with pain
• physical and occupational therapy
• transcutaneous electrical nerve stimulation (TENS), a device that uses electrical impulses to ease pain symptoms

Central sensitization syndrome occurs due to an atypical reaction in the CNS. Although its cause remains unclear, researchers propose that a link between central sensitization and chronic conditions exists.

The condition can be challenging to treat or live with. Pain has physical and emotional aspects, and treatment focuses on treating both. But this requires that a person accept and understand that treatment begins with changing how their brain responds to pain.

People with this condition often go through many years without appropriate treatment or a diagnosis. So it is helpful to work with someone specializing in chronic pain and central sensitization to ensure the most appropriate treatment.