What Is Idiopathic Pain?

Idiopathic Pain Is Well Known Even If Its Cause Isn't

elderly woman with shoulder pain
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Idiopathic pain is also called pain of unknown origin. This is the term doctors use for chronic (long-term) pain, lasting 6 months or longer, that has no identifiable cause. Although its origin is often a mystery, idiopathic pain is very real.

For example, some people feel persistent idiopathic facial pain. They may experience stabbing or burning pain in the face and there is no identifiable nerve or tissue damage that is causing it.

Idiopathic pain may have an unknown origin from the time it begins. It's also possible for this type of pain to remain long after you've healed from a medical condition or injury when, normally, the pain should have stopped.

Which Diseases and Conditions Can Feature Idiopathic Pain?

There are a number of diseases and conditions in which the origin of pain may be known or idiopathic. These include:

  • Fibromyalgia syndrome featuring widespread pain, cognitive impairment (problems with thinking and reasoning), and fatigue.
  • Multiple sclerosis (MS), which can cause pain related to nerve damage and physical disability.
  • Peripheral neuropathy, which causes pain as well as numbness and tingling.
  • Interstitial cystitis, which can cause urinary tract and bladder pain.
  • "Ice-pick" headaches, featuring pain in the optic (eye) nerves.
  • Temporomandibular joint disorder (TMJD), featuring jaw pain and headaches.
  • Fluid pressure in the brain, which can cause headaches as well as dizziness and vision loss.
  • Vulvodynia, pelvic pain in women when there is no identifiable hormonal, nerve, soft tissue, chemical, or infectious cause.
  • Interstitial pulmonary fibrosis, which can cause chest pain as well as a cough and shortness of breath.
  • Irritable bowel syndrome (IBS), featuring pain in the digestive tract.

Which Types of Pain Are Not Idiopathic?

The pain caused by the following diseases and conditions is not idiopathic, even if the underlying cause of a particular disorder is unknown (that is, idiopathic):

  • Pain from a bacterial, viral, or fungal infection.
  • Pain from headaches, including migraines, caused by tension or constricted blood vessels.
  • Pain from inflammation or an injury.
  • Menstrual pain from fibroids, cysts, endometriosis, or adenomyosis (a condition in which the inner lining of the uterus breaks through the uterine wall).
  • Pain from compressed or malfunctioning nerves, such as that from stroke damage.
  • Pain from a hormonal or chemical imbalance detectable with a blood test (seen in a number of autoimmune diseases).
  • Back pain caused by nerve compression, inflammation, or bone or soft-tissue damage.
  • Postoperative pain caused by irreversible inflammation, nerve damage, or soft tissue damage.

Although it’s commonly believed that depression can sometimes cause idiopathic pain, this isn’t the case. However, depression and idiopathic pain can occur together.

Why Is the Cause of Idiopathic Pain Still Unknown?

How pain actually happens is still (mostly) unknown. You’ve probably heard about the progress that’s been made in brain “mapping.” Even though the pain-processing areas of the brain have been mapped, how they ”work” remains a mystery.

A second reason is the relative lack of clinical studies investigating idiopathic pain.

This is largely due to the difficulties involved in studying pain or the brain in human subjects.

Don't Ignore Pain, Whatever Its Cause May Be

If you're having pain and you don't know why, or if you're being treated for pain and not getting the relief you expect, talk to your doctor about what your next steps should be.

Sources:

Benoliel R, Gaul C. Persistent Idiopathic Facial Pain. Cephalalgia. 2017:333102417706349. doi: 10.1177/0333102417706349.

Bramer WM, et al. Lack of Evidence for Central Sensitization in Idiopathic, Non-Traumatic Neck Pain: A Systematic Review. Pain Physician. 2015:18:223-236.

Diatchenko L, Nackley AG, Slade GD, et.al. Idiopathic Pain Disorders--Pathways of Vulnerability. Pain​. 2006;123(3):226-230.

Lipowski ZJ. Chronic Idiopathic Pain Syndrome. Annals of Medicine 1990;22(4):213-217.

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