Trigeminal neuralgia:
understanding and treating lightning-like facial pain

1. What is trigeminal neuralgia?

The trigeminal nerve (nervus trigeminus, literally the “triplet nerve”) is the main sensory nerve of the face. On each side it divides into three branches: one for the forehead and eye, one for the cheek and upper jaw, and one for the lower jaw and chin. In trigeminal neuralgia (neuralgia = nerve pain), short, extremely intense attacks of pain shoot into the area of one or more branches — usually the second or third branch, and almost always on one side only.^¹

An attack lasts only a fraction of a second to two minutes at most, but can repeat many times a day. In between, most people are free of pain. For weeks or months the attacks can occur every day and then stay away for months, sometimes years.^¹,² Because the pain often sits in the jaw, many people first end up at the dentist's.

2. Types: classical, idiopathic, secondary

The International Classification of Headache Disorders (ICHD-3) distinguishes three types — and the classification helps decide which treatment will later be an option:^¹

• Classical — a blood vessel presses on the nerve root at the brainstem so hard that the MRI shows it visibly displaced or thinned. The most common type; here surgery can remove the cause.
• Idiopathic — neither the MRI nor the examination shows an abnormal finding. It is treated in the same way as the classical type.
• Secondary — another condition damages the nerve, such as multiple sclerosis, a usually benign tumour at the cerebellopontine angle or a vascular malformation. Where possible, the underlying cause is treated.

Each type can run a purely paroxysmal course (attacks only) or come with concomitant continuous pain in the same area; this variant is considered harder to treat. It needs to be distinguished from painful trigeminal neuropathy: a more persistent, burning pain, often with numbness, following nerve damage — for example after dental procedures or shingles on the face. It is treated differently.^¹

3. Symptoms: what an attack feels like

People describe the pain as an electric shock, a knife stab or a bolt of lightning — often as the worst pain they have ever experienced.^²

• Lightning-fast onset — out of the blue or after a trigger, peaking immediately, often several attacks in volleys.
• Strictly one-sided — usually the cheek, upper lip, lower jaw, teeth or gums.
• Can be triggered — by harmless stimuli such as chewing, talking, swallowing, brushing your teeth, shaving, putting on make-up or a breath of wind.
• Facial twitching — during severe attacks the facial muscles cramp; hence the old name “tic douloureux”.

Many soon start avoiding the triggers: they eat and drink less, hardly speak and stop brushing their teeth thoroughly. This can lead to weight loss, dehydration and withdrawal. The constant fear of the next attack wears people down — accompanying depression is not uncommon.

4. Causes and risk factors

According to the prevailing explanation, the insulating sheath around the nerve fibres (myelin sheath) is damaged in places at the nerve root. Signals can then “jump” between neighbouring fibres — even a light touch sets off a volley of pain.^¹

• Neurovascular conflict — usually an artery pulsating against the nerve root. Mere contact also shows up on MRI in many healthy people; what matters is whether the nerve root is displaced or thinned.
• Multiple sclerosis — an inflammatory lesion in the brainstem can damage the nerve. In younger patients, with pain on both sides or with sensory disturbances, the practice will consider it; more under Multiple sclerosis.
• Tumours and vascular malformations — rare, usually benign space-occupying lesions at the cerebellopontine angle.
• Hereditary factors — clusters within families point to a genetic component.

5. Diagnosis and telling it apart

The neurologist makes the diagnosis first and foremost on the basis of your description. Additional tests determine the type and rule out other causes.^¹,³

• Medical history: Where is the pain, how long does an attack last, what sets it off, which remedies have you already tried? A pain diary kept over one to two weeks is worth a great deal here.
• Neurological examination: sensation in the face is particularly important — numbness points more towards a secondary type.
• MRI with special sequences: according to the guideline, for every case of trigeminal neuralgia. Thin slices through the brainstem show neurovascular conflicts, MS lesions or tumours.
• Dental examination: early inflammation of the dental pulp or a hairline crack in a tooth can cause similar shooting pain.

What else could be behind it

• Toothache — more throbbing and persistent, often made worse by cold, heat or sweet things.
• Cluster headache — attacks of a quarter of an hour to three hours around the eye, with a watering eye, often at night.
• Migraine — lasting hours to days, pulsating, usually with nausea.
• Nerve pain after shingles — constant burning pain where the rash used to be.

You can find other causes of pain in the head and face under Headache.

6. Treatment: the stepwise approach

Trigeminal neuralgia is treated with medication first — not as needed, but as long-term treatment (prophylaxis), so that attacks do not arise in the first place. Taking a tablet only once an attack has started does not help: it works too slowly for that. To be honest, high-quality comparative studies are scarce; much is based on long experience and expert consensus. In Germany only carbamazepine and phenytoin are approved for this condition; almost all alternatives are used off-label (outside their approved indication).^¹

If medication is not enough, or only works at doses you cannot tolerate, the guideline recommends early neurosurgical advice (section 9). Which substance, dose and combination suits you is decided by the treating practice on the basis of effect, tolerability and your other medicines.

7. Carbamazepine and oxcarbazepine in everyday life

Carbamazepine has been the drug of choice for decades — and at the same time it is one of the drugs with the most interactions of all. Whether treatment succeeds is therefore often decided in everyday life.^¹,⁴

Start slowly, adjust patiently

The dose is increased step by step until the attacks stop or side effects set a limit. Carbamazepine also speeds up its own breakdown (autoinduction): after a few weeks the same dose can work less well. Typical at the start are dizziness, drowsiness, double vision, nausea and an unsteady gait — a real risk of falls in older people, see Dizziness from medications. Whether you can drive is something to clarify with the practice during the adjustment phase.

Lab checks are part of it

• Blood count and liver values: before starting, at short intervals in the first weeks, less often later on. Rarely, the white blood cells drop sharply — fever with a sore throat is always a reason to get in touch.
• Sodium: low sodium shows up as tiredness, headache, nausea or confusion. It is more common with oxcarbazepine, in women and in older age — and is made worse by water tablets (diuretics) or some antidepressants.
• Vitamin D: carbamazepine can lower the level. Whether a vitamin D supplement makes sense is something the practice will clarify.

Interactions: the most important practical point

Carbamazepine revs up liver enzymes that break down many other medicines. Their effect weakens — and rises again once carbamazepine is stopped. The guideline therefore explicitly calls for an interaction check against all your other medicines.^¹,⁴

Skin, genes and pregnancy

Rare but dangerous are severe skin reactions with blisters and involvement of the mucous membranes, usually in the first months of treatment. In people with roots in parts of East and South-East Asia, the risk is linked to a gene variant (HLA-B*1502); the summary of product characteristics recommends a test before starting in these cases.^⁴ Carbamazepine can also harm an unborn child — if you would like to have children, this belongs in the planning early on, see Medications during pregnancy.

8. Acute flare-ups: what helps then

Sometimes the attacks pile up so much that eating, drinking and speaking become almost impossible — an exacerbation. Because a higher dose of the long-term treatment takes days to work, the time in between is bridged with fast-acting medicines, often in hospital:^¹

• Phenytoin by injection — approved, given in hospital under monitoring; less suitable in the long term because of side effects and interactions.
• Lidocaine as a nasal or mouth spray — numbs locally, often well tolerated (off-label).
• Sumatriptan as an injection under the skin — second choice (off-label), not for people with cardiovascular disease.
• Lacosamide — a newer option with a similar mode of action; the evidence is still thin.

At the same time the long-term treatment is always adjusted — bridging does not replace it.

9. Surgery: when it is an option

If medication does not work well enough or is not tolerated, the guideline says neurosurgical advice should be sought early — not only after years. A prerequisite is an MRI that can assess a neurovascular conflict.^¹,³

Which method is right depends on the type, the MRI findings, age, other conditions and your own priorities. No procedure guarantees lifelong freedom from pain. After a successful operation the medication can often be reduced — again only gradually and as agreed. And: treating or pulling healthy teeth does not improve trigeminal neuralgia.

10. Everyday life with trigeminal neuralgia

• Work around triggers wisely — lukewarm, soft food, chewing on the pain-free side, a straw, a scarf in wind and cold.
• Do not give up on oral hygiene — make use of low-pain phases, use a soft brush. Tell your dental practice about the diagnosis and your medicines — especially anticoagulants.
• Take it by the clock, not by the pain — long-term treatment needs a steady level; missed doses can bring attacks back.
• Keep your medication plan up to date — think about interactions with every new prescription and every self-medication; instructions under Create a medication plan.
• Look after your mental health too — self-help groups and psychological pain therapy do not replace medication, but they take away many people's fear of the next attack.

Trigeminal neuralgia is one of the most painful conditions there is — but it is usually treatable. The levers are unspectacular: a confirmed diagnosis with MRI, carefully adjusted long-term treatment, consistent lab checks and a watchful eye on interactions.

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