Trigeminal neuralgia produces brief bursts of facial pain that patients routinely describe as the worst pain they have known. It is also badly misdiagnosed, because the pain is usually felt in the teeth and jaw. Many people have had a root canal or an extraction before anyone names it.
The trigeminal nerve and its three branches
The trigeminal nerve is the fifth cranial nerve and the largest. It carries sensation from the face to the brainstem and drives the muscles of chewing. It splits into three branches, and the pain of trigeminal neuralgia lands in one of them, on one side.
| Branch | What it supplies |
|---|---|
| Ophthalmic (V1) | Forehead, scalp, upper eyelid, and the surface of the eye |
| Maxillary (V2) | Cheek, side of the nose, upper lip, upper teeth and gums |
| Mandibular (V3) | Lower jaw, lower teeth, lower lip, front of the tongue, and the chewing muscles |
Neuralgia most often involves the maxillary or mandibular branch, which is why it is felt in the teeth, and much less often the forehead.
Visual guide
The three trigeminal branches
- Upper branch: Sensation from the forehead and around the eye.
- Middle branch: Sensation from the cheek and upper jaw.
- Lower branch: Sensation from the lower jaw and chin.
Trigeminal neuralgia symptoms
- Sudden and electric, lasting seconds to a couple of minutes, often in volleys
- Triggered by something trivial: brushing teeth, shaving, makeup, eating, talking, cold air
- One side at a time, and reliably in the same territory
- Bouts and remissions, with the bouts becoming more frequent over months and years
Between attacks most people feel normal, though many start avoiding the trigger zone, eating on one side, or skipping meals and dental care. That avoidance is often what a partner notices first. In the atypical form, sometimes called type 2, a constant burning or aching sits in the background between the shocks, and it is harder to treat.
Why it is mistaken for something else
| Condition | How it differs |
|---|---|
| Dental pain | A constant ache, worse with heat, cold, or biting on that tooth, and tender to tapping |
| Cluster headache | Attacks last 15 minutes to 3 hours, centre behind one eye, with tearing and a blocked nostril |
| Migraine | Throbbing, lasts hours to days, with light sensitivity and nausea |
| Bell's palsy | Facial weakness is the main event; the ache behind the ear is dull, not electric |
| Postherpetic neuralgia | Follows a shingles rash in the same area; burning and constant between any stabs |
| Trigeminal neuropathy | Numbness or altered sensation is the main feature, with pain alongside it, after an injury, dental procedure, or shingles |
| Persistent idiopathic facial pain | Daily aching or burning with no trigger zone and no shock-like bursts |
The distinguishing feature is the trigger. Dental pain is a lasting ache that answers to heat, cold, and pressure on one tooth. Trigeminal neuralgia is a burst of shock-like pain lasting seconds, set off by the lightest touch, a breeze, brushing your teeth, or chewing, and it stops as abruptly as it starts. Trigger points can sit inside the mouth as well as on the face, which is why this pain is so often treated as a tooth problem first.
Pain with weakness or numbness is a different problem
Classic trigeminal neuralgia causes pain alone. Facial pain with drooping or weakness on that side, or with definite loss of sensation, points somewhere else and needs prompt evaluation rather than a trial of pain medication.
What causes trigeminal neuralgia
The nerve's insulating coating gets worn away where something presses on it, and the exposed fibers then fire on their own at the slightest provocation.
- A blood vessel looping against the nerve root near the brainstem, by far the most common cause. This is classical trigeminal neuralgia
- Multiple sclerosis, which strips the same insulation from the inside. More likely when the pain starts young or affects both sides
- A tumor at the back of the skull pressing on the nerve, which is rare, or a multiple sclerosis lesion in the brainstem. When an underlying disease like this is the cause, doctors call it secondary trigeminal neuralgia
- No cause found on MRI, called idiopathic, which is treated the same way as the classical form
The names follow the cause. When a blood vessel presses hard enough to visibly change the nerve, it is called classical. When imaging shows no cause at all, it is idiopathic.
Injury, dental procedures, and shingles damage the nerve rather than irritate it, and produce trigeminal neuropathy, with numbness as the main feature.
How it is diagnosed
There is no blood test, and the examination is normal in classic cases. The diagnosis is made from the story: where the pain is, how long each burst lasts, and what sets it off.
An MRI of the brain, with a sequence set up to show the trigeminal nerve, is still worth doing. It looks for a vessel on the nerve, for signs of multiple sclerosis, and for the uncommon tumor. If MS becomes a possibility, an MS evaluation follows.
Visual guide
From the pain pattern to the cause
- Pattern: Brief facial shocks and their triggers are central to the history.
- Imaging: MRI helps look for a cause affecting the nerve.
- Plan: Medication is usually considered first, with other options when needed.
Treatment
Treatment starts with medication and moves to a procedure only when medication stops working or cannot be tolerated.
| Option | Who it suits | Trade-off |
|---|---|---|
| Carbamazepine or oxcarbazepine | Almost everyone, as the first step | Drowsiness and dizziness; needs blood tests to watch sodium and blood counts |
| Gabapentin, pregabalin, lamotrigine, baclofen | When the first drugs fail or are not tolerated | Generally less effective alone; often used in combination |
| Microvascular decompression | Fitter patients with a vessel clearly on the nerve | An operation near the brainstem, but the most durable relief |
| Gamma knife radiosurgery | People who cannot have or do not want open surgery | No incision; relief takes weeks to appear and can fade over years |
| Rhizotomy | When rapid relief matters, or surgery is too risky | Some permanent facial numbness, and the pain can return |
A good response to carbamazepine is itself evidence for the diagnosis. The medication is increased gradually under supervision, which is why the first few weeks usually need several conversations rather than one appointment. We do not perform the procedures; when one is the right step we refer to a neurosurgeon and keep following you.
Microvascular decompression works best when the cause really is a vessel. When multiple sclerosis is the cause, decompression helps far fewer people, so the plan is different.
Between bouts, most people manage by learning their triggers, keeping cold wind off the face, staying on the medication through a remission rather than stopping abruptly, and keeping up dental care, since real dental problems can set attacks off.
When to see a neurologist
Trigeminal neuralgia is a neurologist's diagnosis to make and a neurologist's medication to manage. Dentists are often the first to see it, and neurosurgeons perform the procedures when medication is not enough. See a neurologist for facial pain that is sharp or electric, that fires from a light touch, that keeps returning, or that has not responded to ordinary pain relievers. Facial pain with weakness or numbness needs same-day evaluation.
Dr. Achillefs Ntranos, MD is a board-certified neurologist with fellowship training in multiple sclerosis, and MS is the most common identifiable cause of secondary trigeminal neuralgia. In some people the facial pain arrives before the MS diagnosis, so it is a cause to rule out with an MRI rather than assume away. Because the diagnosis rests on the history, a video visit is a good first step, and he also sees patients in Beverly Hills and Los Angeles through our headache and facial pain service. A first visit is 60 minutes and usually ends with an MRI ordered and a medication started, with a plan for how it will be increased. You can request a visit in Beverly Hills or Los Angeles, or by video anywhere in California.
Frequently asked questions
References
- National Institute of Neurological Disorders and Stroke. Trigeminal neuralgia.
- Cleveland Clinic. Trigeminal neuralgia (TN).
- Cleveland Clinic. Trigeminal nerve: anatomy and function.
- Gronseth G, et al. Practice parameter: the diagnostic evaluation and treatment of trigeminal neuralgia (an evidence-based review). Neurology, 2008.
- Facial Pain Association. Patient resources on trigeminal neuralgia.
- Cruccu G, et al. Trigeminal neuralgia: new classification and diagnostic grading for practice and research. Neurology, 2016.
- Bendtsen L, et al. European Academy of Neurology guideline on trigeminal neuralgia. European Journal of Neurology, 2019.
- Di Stefano G, et al. Trigeminal neuralgia secondary to multiple sclerosis: from the clinical picture to the treatment options. The Journal of Headache and Pain, 2019.
- Barker FG, et al. The long-term outcome of microvascular decompression for trigeminal neuralgia. New England Journal of Medicine, 1996.
- Sultan H, et al. Long-term outcomes of microvascular decompression for trigeminal neuralgia in multiple sclerosis: a systematic review and meta-analysis. Journal of Neurosurgery, 2026.
- de Siqueira SR, et al. Idiopathic trigeminal neuralgia: clinical aspects and dental procedures. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2004.