There’s a lot of good information about it on the Net.
Below is my extract from a University of Manitoba (Canada) web site that describes it clearly, presenting an excellent overview of the condition. The website link is below, and I’d recommend reading it if you are interested. (Note: Links open in a new page or tab, close it to return here)
Trigeminal Neuralgia (Uni of Manitoba)
An Overview of Trigeminal Neuralgia (Tic Douloureux)
Trigeminal neuralgia (TN) is among the most painful afflictions known. It is characterized by sudden attacks of pain that are typically brief, lasting only seconds to two minutes. These attacks are severe and described as intense, stabbing or electrical shock-like. TN pain occurs on only one side, involving the upper, middle and/or lower portions of the face. Each attack may come on spontaneously (without warning) or be triggered by specific light stimulation (gentle touch or movement), usually in the affected areas of the face. Common triggers include touch, talking, eating, drinking, chewing, tooth brushing, hair combing, water from a shower and kissing. Pinching or pressing these same trigger points will not usually cause TN pain.
During an attack of TN, the sufferer will almost always remain still and refrain from speech or movement of the face, so as not to trigger further attacks of pain. The face may contort into a painful wince. Early descriptions of TN confused these sudden attacks with seizures, leading to the term tic doloureux or neuralgia epileptiforme. TN attacks rarely occur when the sufferer is asleep, but may be worsened or alleviated by leaning or lying in a specific position. During an attack, TN pain never crosses over to the other side of the face. In rare cases of bilateral TN, (in which pain occurs on both sides) the left and right-sided pains are separate and distinct.
The disease course of TN is characterized by periods of flare-up (i.e. exacerbations), when painful attacks come on often and may be very difficult to control with medications. Then there are periods of remission, when no pain occurs. However, even during periods of remission, TN sufferers live in fear of their next flare-up. Over time the periods of exacerbation become more frequent and more severe, while the remissions become shorter. Therefore, the need for more aggressive medical or surgical treatments increases as the disease invariably progresses.
In typical TN, (see Types of Trigeminal Neuralgia and Their Causes) sufferers are free of pain between attacks. However, in severe or long-standing TN, an aching pain or subtle numbness may develop in the affected trigeminal distribution. During severe exacerbations, attacks of pain may occur repeatedly so that the sufferer feels nearly constant pain.
The diagnosis of typical TN is based upon the description of the sufferer’s pain and associated features. Neurological and cranio-facial examinations and special tests are usually normal. Therefore, doctors and dentists seeing patients with facial or dental pain must be alert to the possible diagnosis of TN. A careful trial of medical therapy will usually confirm the diagnosis of TN (see Medications).
TN sufferers often endure years of suffering and misdirected treatments before the disease is recognized. Some of the erroneous diagnoses often encountered include various dental diseases, temporomandibular joint disorders, paranasal sinus infections, ophthalmic (eye) pain syndromes, temporal arteritis, ice pick-like migraine pain, facial migraine, myofascial pain, idiopathic facial pain and psychological disorders. Even today we find that of our patients have undergone several unnecessary and useless “treatments” before the TN was accurately diagnosed. Some misdirected interventions include dental extractions, root canals, nasal sinus surgeries, biopsies, salivary gland procedures and medical treatments involving antibiotics and narcotics. The difficulty in diagnosing TN is in part due to the lack of confirmatory clinical, laboratory or radiological tests, periods of spontaneous remission that may be confused with a cure for the disorder, and the relative rarity of TN.
TN is present in 100 to 200 people per 100 000, and new TN cases occur in 5 people per 100 000 each year. Onset is more frequent in people of later ages (i.e. 25 new cases per 100 000 people over 70 years old). While the average age of onset for TN occurs in the 50s and 60s, young adults and even children may develop typical TN or other types of TN (see Types of Trigeminal Neuralgia and Their Causes). Women are nearly twice as likely to develop TN compared to men. Two percent of sufferers will also develop TN on the other side of the face (bilateral TN). There are rare occasions when TN appears to run in a family (i.e. familial tendency).