The Watering Eye and the Blocked Nostril: The Nerve Reflex Behind Cluster Headache and Migraine

What this video covers

• Why cluster headache and migraine involve a nerve reflex between the face and the brainstem, not just blood vessels
• Where the sphenopalatine ganglion sits, in a pocket behind the nose, and why it can be reached through the nose
• How the through-the-nose, through-the-mouth, and image-guided approaches differ in precision and risk
• What the randomized data really show, including one trial that missed its main goal
• How long relief usually lasts — hours to days per block, sometimes weeks with a series — and why it is a bridge, not a cure
• The real risks: bitter taste, a numb palate, nosebleed, nausea, and fainting. Needle approaches add cheek numbness, bleeding from the maxillary artery, infection, short-term double vision, and rarely a seizure if numbing drug enters a vessel
• MEDICAL DISCLAIMER: This content is for educational purposes only and is not medical advice. It does not substitute for professional diagnosis or treatment. Always consult a licensed healthcare provider regarding your condition. Viewing this video does not establish a doctor-patient relationship.

The watering eye and blocked nostril of a cluster headache or one-sided migraine are a nerve reflex, not sinus disease. Pain signals from the face drive the brainstem. The brainstem fires back through the sphenopalatine ganglion behind the nose. That signal lands on the tear gland and the lining of the nose, on the same side as the attack.

It is one forty in the morning and you are awake again. Fourth night running, same side, behind the same eye. The pain does not throb — it bores. The eye streams. The nostril closes. The lid droops. You pace, because holding still is unbearable. Or your version is a one-sided migraine with a watering eye and a blocked nostril that everyone keeps calling sinus.

That combination — pain on one side, plus a watering eye and a closing nostril on that same side — is not chance. And it is not your sinuses. It is a reflex, wired into a bony pocket behind your nose. This article explains what that reflex is and why it causes exactly what you feel. It explains why it gets mistaken for sinus disease for years. And it covers what the published evidence honestly supports about calming it.

What is the sphenopalatine ganglion?

Behind your nose, on each side, sits a narrow space called the pterygopalatine fossa. It is an upside-down pyramid tucked in behind the cheek sinus. Inside it is the sphenopalatine ganglion, sometimes called the pterygopalatine ganglion. It is about the size of a pea.

Call it a junction box rather than a nerve, because that is what it does. Two different cable bundles meet there:

• Sensory fibers from the maxillary division of the trigeminal nerve (the face nerve’s upper-jaw branch) pass through it.
• Parasympathetic fibers (the “rest and digest” nerves) arrive by way of the greater petrosal nerve, coming from the brainstem.

Here is the loop that matters. Pain signals from the face enter the brainstem. The brainstem drives the outgoing arm of that reflex. That arm relays through this ganglion. Its outgoing fibers fire onto your tear gland and the lining of your nose. At the nerve endings they release vasoactive intestinal peptide and PACAP (pituitary adenylate cyclase-activating polypeptide).

That is the whole circuit: face → brainstem → ganglion → eye and nose.

Why does a cluster headache make your eye water and your nose run?

Now put the mechanism next to what you actually feel.

The streaming eye is the tear gland being switched on. The blocked, running nostril is the nose lining being switched on. Neither one is infection, allergy, or inflamed sinus tissue. They are the efferent output of a reflex that your pain turned on. That is exactly why they arrive with the attack, sit on the same side as the attack, and leave when the attack leaves. Sinus disease does not keep that kind of schedule.

You may have been told two things that are wrong, and both matter.

First, the drooping eyelid and small pupil of a cluster attack are not spillover from this ganglion. They are a partial Horner sign — a sympathetic finding, from the other branch of the autonomic (automatic) nervous system. Blaming them on the sphenopalatine ganglion is a common and understandable mistake. But it is still a mistake.

Second, the vasodilation so often blamed for the pain is a correlate, not the engine. Blood vessels do widen during an attack. But that widening rides along with the attack. It does not cause it. The signal comes first.

This has a result you should hear before anyone reaches for a needle. Calming that ganglion can interrupt the outgoing arm of the reflex and the fibers passing through it. But it does not switch off the brainstem generator that started the attack. Every honest claim about this procedure follows from that one sentence.

Why are cluster headaches mistaken for sinus problems?

Think about what happens to a person whose headache comes with a running nose and a blocked nostril. They get sent to the wrong organ, and they stay there.

A blocked nostril, a running eye, pain over one cheek. To a doctor working an eleven-minute slot from a template, that reads as sinus disease. Antibiotics follow. A scan is ordered and reads normal. The published case reports include people who had sinus surgery, then more sinus surgery, then a tooth pulled. All for a reflex that lives in neither the sinus nor the tooth.

The most telling fact about you is usually the one nobody asks about: the tearing eye, and whether it is on the same side as the pain, and whether it comes and goes with the attack. That is not a hard question. It is a question that needs someone to have time.

None of this means the doctors involved were careless. What a template cannot do is name a nerve reflex like this one, because nobody asked the question that would have brought it out.

Before anything else: danger, then pattern

There is an order to follow here. Skipping it is how people get injected for the wrong problem.

Rule out the dangerous causes first

These are checked urgently, not treated with an elective block:

• Thunderclap onset — the worst headache of your life, peaking within seconds. That is an emergency tonight.
• Fever with a stiff neck.
• A first severe headache after age fifty.
• Any focal neurologic deficit — weakness, numbness, or a change in vision or speech.
• Any headache after head trauma.

How is cluster headache different from migraine and other one-sided headaches?

The one-sided headaches that come with eye and nose signs are a family — the trigeminal autonomic cephalalgias. They are not interchangeable. Getting this wrong is not a small thing. Two members of the family are ended by a tablet.

• Cluster headache. Untreated attacks run 15 to 180 minutes, up to eight a day. The pain is on one side, around or behind the eye. You are restless — you pace rather than lie down.
• Migraine. Attacks run 4 to 72 hours, and you want to lie still.
• Paroxysmal hemicrania. Looks like short cluster attacks, but responds absolutely to indomethacin.
• Hemicrania continua. One-sided pain with the same eye and nose signs that never fully switches off. It too responds absolutely to indomethacin. Miss it and you have injected a headache that a tablet would have stopped.
• SUNCT and SUNA. Stabbing attacks lasting seconds to minutes, dozens or hundreds a day. They respond to sodium-channel drugs such as lamotrigine — not to this ganglion.

The pattern is the diagnosis. And much of the pattern lives in facts only you can collect. Start an attack diary tonight and write down the hour.

A block is not first-line, and nobody should pretend otherwise

Maybe nobody has put you on high-flow oxygen through a non-rebreather mask. Maybe nobody has offered an injectable triptan or started a genuine preventive. If so, the gap in your care comes before any procedure. Fix that first.

A sphenopalatine ganglion block is for the person who has already done those things and is still losing their nights.

Three routes in, three different risk profiles

If a block makes sense, know that “the block” is really three different procedures.

Transnasal (through the nose) is the least invasive. There are two versions, and they are not interchangeable. The older one soaks a cotton swab in numbing drug and parks it against the nose lining. It is cheap and common, with no placebo-controlled data behind it. The version tested in both randomized trials used a small nasal applicator. It delivered a measured 0.3 cc of 0.5% bupivacaine per side, past the back end of the middle turbinate. There, about a millimeter of lining separates the drug from the ganglion. No needle enters tissue with either version. You have a right to be told which one you are getting.

Transoral (through the mouth) passes through a small opening in the roof of the mouth.

Percutaneous (through the skin) enters below the cheekbone under live X-ray, with contrast confirming spread. It is the most precise route and carries the highest risk, because the maxillary artery shares that space. Details on how each route is done and what the visit involves are on the sphenopalatine ganglion block treatment page.

Patients also ask about diet and light. A ketogenic diet, omega-3-derived pro-resolving mediators, and 660 to 850 nanometer light are untested in cluster headache and migraine. No randomized trial shows that any of them shortens a bout or stops an attack. You can fairly track them in a diary. They should not push aside oxygen, a triptan, or a tested preventive.

What the trials actually found — including the one that failed

This is the section most brochures leave out.

A small placebo-controlled pilot in chronic migraine showed promise, not proof. Cady and colleagues published a double-blind, placebo-controlled pilot in Headache in 2015. Adults with chronic migraine got repeated bupivacaine or saline through the nose. Pain scores were lower with bupivacaine at 15 minutes, 30 minutes, and 24 hours. But 38 patients finished, split 2:1. So the whole placebo comparison rests on 12 people. And it used a single commercial nasal device. The authors’ own word was promise. Also, the HIT-6 headache-impact gain in that paper was a within-group change in the bupivacaine group. The paper reports no comparison between groups. So no one may claim it beat placebo on that measure. (Early signal, not established efficacy.)

The 87-patient emergency department trial missed its primary endpoint. Schaffer and colleagues, in Annals of Emergency Medicine the same year, randomized 87 emergency department adults with undifferentiated acute headache. These were general headaches — not confirmed migraine, not cluster. It is not a bigger version of the migraine pilot. It is a different group entirely. The main goal failed: 48.8% versus 41.3% reached 50% pain relief at 15 minutes. That is an absolute difference of 7.5%, with a confidence range of −13% to +27.1%. That range crosses zero. Its 24-hour edge was a secondary, multiplicity-unadjusted outcome. It does not rescue a failed main result. (Negative trial. It is reported here because it is real.)

The systematic review’s headline is narrower than it sounds. Ho and colleagues, in the Journal of Headache and Pain in 2017, reviewed 83 publications. Only 23 were stronger than case series (small groups of case reports). They concluded the strongest evidence at this target is in cluster headache. That is accurate. But it pools blocks with radiofrequency ablation and implanted neurostimulation. Those are three different treatments with three different risk levels. The authors themselves note the controlled studies were small and never repeated. (Contested. Do not read a pooled statement as a block-only efficacy claim.)

Now the uncomfortable sentence, said plainly: there is no randomized, placebo-controlled trial of a sphenopalatine ganglion block, by itself, in criteria-confirmed cluster headache. Not one. The only placebo-controlled block data in a defined headache group is that 38-patient migraine pilot. Everything else is uncontrolled case reports, or ablation and stimulator trials. Those are different procedures, not evidence for a nasal applicator.

The honest grade for this evidence is low. A block can still be a fair option for a carefully chosen patient, offered with that grade said out loud. When it helps, relief usually runs hours to days from a single block. A series may stretch that to weeks. But that duration comes from clinical experience and uncontrolled case reports, not from any controlled trial. It is a bridge that buys a window. It is not a cure.

Risks, and who should wait

Common and temporary: bitter taste, a numb palate, nosebleed, nausea, and a fainting-type drop in blood pressure.

Added by needle approaches: cheek numbness, a nicked maxillary artery with bruising, rarely bleeding behind the eye or double vision, infection, and seizure if numbing drug enters a blood vessel.

Deferred with: an active nose or sinus infection, full-dose blood thinners, or a known allergy to numbing drugs.

An honest picture of a real course

What follows is a composite — a picture assembled from many patients with this condition, not one person’s chart.

A man in his forties. Bouts arrive every spring and every autumn, several attacks a night, always the same side. Behind him is a decade of treatment aimed at his sinuses and his teeth.

What helped first was not a procedure. It was a diagnosis, and a diary that made the timing undeniable within two weeks. What went in first was oxygen. That meant a tank and a non-rebreather mask at high flow, which nobody had given him in that whole decade. He also got an injectable attack drug and a preventive, adjusted while watching his heart tracing. The block came after, as a bridge while the preventive reached full dose.

His attacks got shorter. Not gone. Shorter. The first block did almost nothing he could measure. The second, better placed, bought about two days. He had a nosebleed. The bout still ran most of its course. If three blocks had changed nothing lasting, the right move would have been to stop, not escalate.

This is something seen in practice, not a trial result. Individual results vary.

Frequently asked questions

Key takeaways

• The watering eye and blocked nostril of a one-sided headache come from a nerve reflex. It relays through the sphenopalatine ganglion behind your nose. It is not sinus disease.
• The drooping lid and small pupil of a cluster attack are a partial Horner sign, from the sympathetic nerves. And the widened blood vessels of an attack go along with it; they do not cause it.
• A block can interrupt the outgoing arm of that reflex. But it does not switch off the brainstem generator. That is exactly why relief runs hours to days, not forever.
• The evidence is graded low. There is one 38-patient placebo-controlled migraine pilot and one negative 87-patient emergency department trial in general headache. There is no placebo-controlled block trial in confirmed cluster headache.
• Oxygen, an injectable triptan, and a real preventive come before any procedure. Dangerous causes of headache get checked, never injected.

This article is educational and is not a substitute for evaluation, diagnosis, or treatment by a physician. Individual results vary. Do not start, stop, or change any medication without consulting your physician. To have a one-sided headache with autonomic features properly evaluated before any procedure is scheduled, call (314) 481-5000 or text (314) 886-5902.

References

1. Cady R, et al. A double-blind, placebo-controlled study of repetitive transnasal sphenopalatine ganglion blockade with Tx360 as acute treatment for chronic migraine. Headache. 2015;55(1):101-16. PMID 25338927. PubMed
2. Schaffer JT, et al. Noninvasive sphenopalatine ganglion block for acute headache in the emergency department: a randomized placebo-controlled trial. Ann Emerg Med. 2015. PMID 25577713. PubMed
3. Ho KWD, et al. Sphenopalatine ganglion: block, radiofrequency ablation and neurostimulation – a systematic review. J Headache Pain. 2017. PMID 29285576. PubMed

In an active cluster bout?

A sphenopalatine ganglion block takes only a few minutes. It uses no needle through the skin and no sedation. It is often used during a bout to break the cycle. The Padda Institute offers same-day and emergency visits — no referral needed, and you do not need to be a current patient. Call or text us.

Medically reviewed by Dr. Gurpreet Singh Padda, MD, MBA, MHP — Board Certified in Anesthesiology, Pain Medicine, Interventional Pain Management, Addiction Medicine, and Obesity Medicine. Last reviewed July 2026.

Dr. Gurpreet Singh Padda, MD, MBA, MHP