A 40-year-old woman complains of episodes of severe unilateral, stabbing facial pain that is intermittent for several hours, and then disappears for several days. Physical examination is entirely normal. Which of the following is the most likely diagnosis?

The cause of trigeminal neuralgia (tic douloureux) is unknown, although some cases may be caused by compression of the trigeminal nerve by arteries or veins of the posterior fossa. The pain occurs in paroxysms and is strictly limited to one or more branches of the fifth cranial nerve. Paroxysms may be brief or last up to 15 minutes. There is no objective sensory loss, but the patient may complain of hyperesthesia of the face. Watering of the eye on the involved side may occur during an attack.