Table 1.

Persistent pain syndromes with idiopathic or poorly understood etiology.^1–16.

Pain syndrome(s)	Associated tissue(s)	Estimated prevalence
Bladder pain syndrome/Interstitial cystitis	Bladder	2–6.5%
Vulvodynia	Perineum	7–8% of women
Severe headaches or migraine	Skeletal muscle, meninges, trigeminal nerve, and cranial vessels	14–23%
Fibromyalgia syndrome/chronic widespread pain	Skeletal muscle	2–8%
Regional myofascial pain	Skeletal muscle	Unknown, common
Chronic low back or neck pain	Skeletal muscle, fascia, intervertebral discs, and facet joints	10.2%a (low back pain)
		2.2%a (neck pain)
Idiopathic orchialgia	Testis, epididymis, and perineum	4.8% of men presenting to urology clinics
Irritable bowel syndrome	Small intestine	4–6%
Gastroesophageal reflux disease	Esophagus	17–18%b

^aPercentage of U.S. adults reporting chronic impairing low back or neck pain for >3 months in North Carolina, USA.

^bPercentage of U.S. adults with painful reflux in Olmstead County, MN, USA.