Primary Headache Disorders: Trigeminal Autonomic Cephalgias and Migraine

Patient Expert
Medically Reviewed

Although we talk more about migraine than other headache disorders here, there are more than 300 headache disorders. The International Classification of Headache Disorders, 3rd edition (ICHD-3) of the International Headache Society identifies four main categories of _ primary headache disorders_ migraine, tension-type headache, trigeminal autonomic cephalgias (TACs), and "other primary headache disorders." Dr. Peter Goadsby, a migraine and headache specialist at the University of California at San Francisco, discussed the characteristics of the trigeminal autonomic cephalgias and how to differentiate them from migraine at the American Headache Society's 2014 Scottsdale Headache Symposium.

What Are Trigeminal Autonomic Cephalgias?

Trigeminal Autonomic Cephalgias consist of cluster headaches, paroxysmal hemicrania, short-lasting unilateral neuralgia headaches with conjunctival injection (SUNCT) and hemicrania continua. TACs have symptoms that are consistent with autonomic nervous system activation. The autonomic nervous system is the part of the nervous system that regulates body processes that are automatic or reflexive. An example of automatic or reflexive symptoms includes tearing of the eyes. Anatomically, the trigeminal cervical complex is involved. Dr. Goadsby refers to this as the "head pain nerve." The trigeminal nerve is the primary sensory nerve of the head and face and consists of three branches mandibular, maxillary, and ophthalmic.

Characteristics of Trigeminal Autonomic Cephalgias:

Dr. Goadsby notes that all of the TACS have cranial autonomic symptoms as a result of trigeminal autonomic reflexes. These cranial autonomic symptoms may include:

There are, however, important differences among the TAC's that help with differentiating among them for diagnosis of these disorders. For example, cluster headaches are seen more commonly in men; whereas, paroxysmal hemicrania and SUNCT are seen more often in women. It is important to note, however, that this is not exclusive and that both men and women can experience any of these disorders. It's the attack frequency and duration of the pain that is helpful in determining which of the TAC's an individual is experiencing. The following chart depicts both frequency and duration for cluster headaches, paroxysmal hemicrania, and SUNCT.

  **Attack Frequency a Day** **Duration**
**Cluster Headaches** 1-8 15-180 minutes
**Paroxysmal Hemicrania** 11 2-30 minutes
**SUNCT** 10-200 5-240 seconds

Responsiveness to medication can also be a helpful diagnostic tool in that paroxysmal hemicrania always responds to indomethacin, while neither cluster headaches nor SUNCT respond to indomethacin. Additionally, 75% of those with cluster headaches are responsive to oxygen; whereas, neither paroxysmal hemicrania nor SUNCT respond to oxygen. In the case of sumatriptan, there is a 90% cluster headache response rate, a 20% paroxysmal hemicrania response rate, and a less than 10% SUNCT response rate.

Goadsby notes that about 90% of patients with TAC's have cluster headaches. The World Health Organization (WHO) reports that cluster headaches impact approximately 1 in 1,000 adults. While it used to be believed that only adults suffered from cluster headaches, we now know that children (generally 10 years of age and older) and adolescents may also experience cluster headaches. Individuals with cluster headaches experience at least one of the cranial autonomic symptoms identified earlier. They may also experience significant restlessness or agitation and the need to move or rock. Cluster headache symptoms are primarily unilateral. The pain is generally orbital (having to do with the eyes), and patients may report that their sinuses feel full. Goadsby indicates that 90% of those with cluster headaches have accompanying ear symptoms, such as ear fullness. Because of this and the other cranial autonomic symptoms, many cluster headache patients are initially diagnosed with sinus congestion or episodic sinus pain.

About 50% of cluster headaches are accompanied by migrainous features, including photophobia, phonophobia, or nausea. This is also true of paroxysmal hemicrania and SUNCT. It should be noted, however, that these migrainous features are generally unilateral in TAC's.   While this is not a hard and fast rule, it is a good generalization when determining whether one is experiencing cluster headaches or migraines.

Differentiating Between Cluster Headaches and Migraines?

Dr. Goadsby stresses the need for a thorough patient history with questions about pain symptoms and location, autonomic features, frequency and duration. He also emphasizes the need for physicians to pay attention to patients' non-verbal cues when responding to questions. While patients may not describe their experiences in the same terms that a physician does, he notes that their non-verbal behavior provides insight to the degree to which they can personally relate to the questions that are being asked. The following chart looks at the differences between migraines and cluster headaches.

  **Cluster Headache** **Migraine**
Gender Predominantly male Predominantly Female
Location 100% unilateral 66% unilateral
Duration 15 to 120 minutes 4-72 hours
Frequency Comes in clusters or groups No clear-cut pattern
Migrainous Features Unilateral Diffuse
Nausea 50% 80%
Photophobia 56% 85%
Exacerbated with


No Yes
Family History Yes Yes
Aura 14% 30%
Autonomic Features Yes Infrequently
Restlessness/Agitation Yes Infrequently

A Word to Patients

While it's not the responsibility of the patient to diagnose their specific headache disorder, it is important that the patient pay close attention to their symptoms and the duration and frequency of those symptoms. A headache and migraine diary is an essential tool in helping the patient to track the nature of their headache and its accompanying symptoms. By looking over a diary, patients are better equipped to know the precise duration and frequency of their symptoms. The diary is a tool that the patient and the physician can use in tandem with one another to help in diagnosing and treating the specific headache disorder.

Clearly, there is overlap among the TAC's and even between migraines and cluster headaches. Diagnosis is not an exact science. There are currently no imaging procedures or blood tests that can definitely identify the kind of primary headache disorder an individual has. For this reason, thorough self-reporting, physician questions about symptoms, and even responsiveness to medications are essential components to the accurate diagnosis of specific headache disorders.

Do you keep a thorough migraine and headache diary? Does it include pain location, frequency and duration? Does it include other symptoms? Does it include medication use and response? Do you take your headache diary to your medical appointments and discuss it with your physician Only with accurate reporting in a migraine and headache diary can a patient and a physician accurately and fully analyze both the nature and the treatment of the headache disorder.


Goadsby, Peter J. "Trigeminal Autonomic Cephalgias, Secondary and Imaging Headaches." Lecture, Scottsdale Headache Symposium from American Headache Society, Scottsdale, November 21, 2014.

Wishing you health, hope & happiness,

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