How do TAC (trigeminal autonomic cephalalgia) headaches differ from migraine?


TAC headaches include cluster and hemicrania-type headaches. Cluster headaches are shorter lasting and more painful than migraine.


“Trigeminal autonomic cephalalgias is a mouthful, so that's why we call them TACs or T-A-C. The trigeminal autonomic cephalalgias are a different type of primary headache disorder. We have what we call primary headache disorders and then there are secondary headache disorders. Secondary headache disorders are when something else is causing your headache, like an infection or a brain tumor. Those are what we call secondary headache disorders. But then there are many primary headache disorders, which are likely related to genetics, such as migraine, and then another one are the TACs, or trigeminal autonomic cephalalgias, and that is a collection of disorders and they all have some similar characteristics. The most common of those headache disorders is cluster or cluster headache.

“The commonality in all of those disorders is they have what we call side-locked headaches. They are only on one side, for example let's say the right side. This is different than migraine, where patients will say, ‘Well it starts over on the right side but then it kind of goes over to the left when things get worse and everything hurts.’ Whereas, with patients with cluster headache, their headache will primarily stay on that one side because they're side-locked.

“The other thing that's very common in these disorders and have to be present to meet the diagnostic criteria is they have what we call one-sided, or unilateral autonomic features. The autonomic nervous system is a part of our nervous system that is in control of our fight-and-flight reactions. With that system, when it becomes activated in patients that have TACs, or trigeminal autonomic cephalalgias such as cluster headache, they will have symptoms where they have tearing of one eye. So, if there's pain on the right side, they'll be maybe tearing in the right eye, redness of the right eye, droopiness of the right eyelid, nasal congestion and runny nose just out of the right nostril, flushing of the face just on that right side.

“The other thing that really differentiates migraine from the TACs such as cluster headache, is what you do when you're having an attack. Migraine patients want to be as still as possible. They want to go into a dark room that's quiet and just lay there curled up in a ball. They don't want even anyone to come and sit on the bed because that will cause movement. Whereas in patients with TACs such as cluster headache, they become very restless. They have to pace the room and the pain is so severe. This pain is known to be the most severe pain that mankind has felt. Some people will call this suicide headaches because the pain is so severe. During that painful attack, people feel like they need to pace the room, people have punched walls, people cannot sit still at all. So that restlessness is very common in those TACs and very uncommon in migraine.

“The other trigeminal autonomic cephalalgias — although I said cluster headache’s the most common one — the other ones are things called paroxysmal hemicrania, SUNCT or also hemicrania continua. Those are the TAC disorders.”


TAC headaches are primary headaches that are probably genetically related, like migraine. Cluster headaches are TACs. Pain occurs on only one side of the head with tearing, redness, and droopiness of the eye, and nasal congestion or runniness on that side of the head. During an attack people are not able to sit still.

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Amaal J. Starling, MD, FAHS, FAAN

Mayo Clinic, Arizona

Dr. Amaal J. Starling is an associate professor of neurology at the Mayo Clinic College of Medicine. She joined the Mayo Clinic in 2012 and is currently a consultant within the Department of Neurology. Dr. Starling received her medical degree from the Drexel University College of Medicine in Philadelphia. She completed a transitional year residency, a neurology residency, and a headache fellowship at the Mayo Clinic College of Medicine in Scottsdale, Ariz.

Dr. Starling is an active member of numerous migraine advocacy organizations, including the American Headache Society (AHS), the American Migraine Foundation, and the American Academy of Neurology (AAN). She is also involved in events supporting migraine, including Headache on the Hill, Miles for Migraine, and the Alliance for Headache Disorders Advocacy. Dr. Starling is currently serving on the AHS Board of Directors and is the chair of the AHS Advocacy Committee and a member of the AHS Diversity, Equity, and Inclusion Taskforce. Dr. Starling has been the recipient of numerous awards, including the AHS Above and Beyond Award for Service, Manfred D. Muenter Award for Excellence in Clinical Neurology, the AAN Annual Meeting Residency Scholarship, the 2012 Spirit of Mayo Clinic Award, and the Mayo Brothers Distinguished Fellowship Award.

Dr. Starling has authored numerous peer-reviewed publications and abstracts related to her fields of interest, which include migraine, concussion, post-traumatic headache, neuromodulation, and telemedicine. Dr. Starling’s hope is that her research and advocacy will advance care for people with migraine, post-traumatic headache, and other headache disorders. She envisions a future in which all people with headache disorders receive personalized, effective, and well-tolerated treatment options to improve their quality of life.

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