It most often occurs in the middle of the night and lasts from seconds to minutes; pain and aching lasting twenty minutes or longer would likely be diagnosed instead as levator ani syndrome. In a study published in 2007 involving 1809 patients, the attacks occurred in the daytime (33 percent) as well as at night (33 percent) and the average number of attacks was 13. Onset can be in childhood; however, in multiple studies the average age of onset was 45. Many studies showed that women are affected more commonly than men, but this can be at least partly explained by men's reluctance to seek medical advice concerning rectal pain. Data on the number of people afflicted vary, but prevalence may be as high as 8–18%. It is thought that only 17–20% of sufferers consult a physician, so obtaining accurate data on occurrence presents a challenge. During an episode, the patient feels spasm-like, sometimes excruciating, pain in the rectum and/or anus, often misinterpreted as a need to defecate. To be diagnosed as<unk> , the pain must arise de novo (meaning the absence of clear cause). As such, pain associated with constipation (either chronic, or acute), penetrative anal intercourse, trauma (such as tears or fissures of the rectal sphincter or anal canal), side-effects of some medications (particularly opiates), or rectal foreign body insertion preclude this diagnosis. The pain episode subsides by itself as the spasm disappears on its own, but may reoccur. Because of the high incidence of internal anal sphincter thickening with the disorder, it is thought to be a disorder of that muscle or that it is a neuralgia of pudendal nerves. It is not known to be linked to any disease process.
Proctalgia fugax
Barodontalgia
Polio-like syndrome
Dysbarism
Amaurosis fugax
Hemifacial spasm
Lonomia
Bobble-head doll syndrome