Trigeminal neuralgia, or tic douloureux, is a chronic neurologic disorder of the fifth cranial nerve (trigeminal nerve) that causes a characteristic facial pain. The pain associated with trigeminal neuralgia is typically sharp, brief (lasting seconds to 2 minutes), unilateral, and in the distribution of one or more branches of the trigeminal nerve. However, a quarter to half of patients have concomitant continuous pain in the territory of the trigeminal nerve, which is termed trigeminal neuralgia with concomitant continuous pain (formerly type 2 trigeminal neuralgia). The right side of the face is affected more often than the left side. Sensory and motor deficits are absent. There is often a location on the face that triggers the pain, so activities such as shaving, teeth brushing, or face washing may bring on a painful episode. Triggered paroxysmal pain is reported in almost all patients. Attacks occur for periods of time, often followed by spontaneous remission. The pain, however, will typically return within months to years. Patients with severe disease can experience poor quality of life and may be at increased risk for suicidal thoughts. 

The annual incidence of trigeminal neuralgia is about 5 people per 100 000. It can occur at any age but is more common in people older than 50 years. It is about twice as common in women compared with men.

There are 3 types of trigeminal neuralgia: classical, secondary, and idiopathic. The 3 forms may be clinically indistinguishable. Classical is the most common, accounting for 75% of cases, while secondary and idiopathic account for 15% and 10%, respectively. Classical is caused by intracranial vascular compression of the trigeminal nerve root. Secondary is attributable to an identifiable neurologic disease, such as multiple sclerosis or benign tumors in the cerebellopontine angle. For patients with multiple sclerosis, the risk of trigeminal neuralgia is increased by a factor of 20. In idiopathic trigeminal neuralgia, no apparent cause of nerve disturbance is found.

Carbamazepine is the most common treatment for trigeminal neuralgia and is effective in more than half of patients. There are several other medications and interventional treatments available for refractory cases.