SUNCT syndrome

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SUNCT syndrome
Frequency50 described cases (as of 2015)[1]

Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT syndrome) is a rare headache disorder that belongs to the group of headaches called trigeminal autonomic cephalalgia (TACs).[1] Symptoms include excruciating burning, stabbing, or electrical headaches mainly near the eye and typically these sensations are only on one side of the body. The headache attacks are typically accompanied by cranial autonomic signs that are unique to SUNCT. Each attack can last from five seconds to six minutes and may occur up to 200 times daily.

TACs are caused by activation of the autonomic nervous system of the trigeminal nerve in the face.

As of 2015 about 50 cases have been described in the medical literature.[1] Onset of the symptoms usually come later in life, at an average age of about 50. Although the majority of patients are men over the age of 50, it is not uncommon to find SUNCT present among other age groups, including children and infants.

Signs and symptoms

Left eye of the person during a SUNCT syndrome attack.

People affected by SUNCT often describe their headache attacks as excruciating pain. The attacks are severe enough to disrupt daily activities, but hospitalization is not necessary for most affected individuals.[citation needed]

Frequency and duration

The average number of attacks per day is around 60, ranging from 3 to 200 times.[2]

The attacks can be divided into three groups: single stabs, groups of stabs, and attacks with saw-tooth pattern, from the shortest to the longest duration respectively. The attacks usually last from five seconds to 240 seconds. Typically, longer attacks are more painful due to psychological effects, and patients often feel agitated before and during the attack. They occur mostly in the orbital, supraorbital, or temporal region, but can also occur in the retro-orbital (behind the orbit of the eye) region, side, top, and back of head, second and third trigeminal divisions, teeth, neck, and ear.[citation needed]

Cranial autonomic symptoms associated with headache attacks

SUNCT often accompanies cranial autonomic symptoms, including lacrimation (tear flow), ipsilateral ptosis (drooping of the eyelid which is on the same side as the attacks), eyelid edema (swelling due to fluid accumulation), nasal blockage, and conjunctival injection (redness of eye). Depending on which division of the trigeminal nerve innervates the area affected, autonomic symptoms may be less obvious. Short-lasting unilateral neuralgiform headache attacks with cranial autonomic features (SUNA) is a subset of SUNCT and may be diagnosed when fewer autonomic symptoms are observed during attacks.[citation needed]

The majority of SUNCT attacks occur chronically; however, some occur episodically. In chronic SUNCT, attacks can occur regularly or irregularly without a distinct refractory period, whereas in episodic SUNCT, attacks occur only for a certain period of time and then cease for another period. Episodes of attacks last from a few days to a few months, and up to 22 attack episodes in one year have been observed. SUNCT can go into remission even after a chronic period, and relapse either spontaneously or due to some stimulus.[2]

Triggers of headache attacks

Most of the time SUNCT occurs spontaneously; however, attacks can be triggered by simple daily stimuli such as touching the face or scalp, washing, chewing, eating, talking, coughing, blowing nose, or showering. They also can be triggered by light (including sunlight and fluorescent lights) and injuries. Stimuli capable of triggering a cluster headache, including alcohol, smoke, strong smells and a warm environment, can also trigger SUNCT in a few patients.[2] In some cases, patients with episodic SUNCT only exhibit symptoms biannually, in spring and fall. This periodicity suggests that the hypothalamus, which is responsive to day length and photoperiod for regulating circadian and seasonal rhythms, has a role in its triggering.[3]


The pathophysiology of SUNCT is incompletely understood. Recent studies suggest the existence of a relationship between the hypothalamus and the condition. Functional MRI and deep brain stimulation of a large patient pool showed activation of the posterior hypothalamus during attacks of primary SUNCT, on both sides and contralaterally (on the opposite side).[4] Functional MRI studies suggest brain stem activation during attacks as well.[5] Activation of the trigeminocervical complex and other related structures results from innervation from branches of trigeminal and upper cervical nerves.[6] There exists a direct connection between trigeminal nucleus caudalis, which is located in the brain stem, and the posterior hypothalamus. Therefore, it is possible that stimulation of the peripheral trigeminal nerve activates the hypothalamus and the hypothalamus in turn communicates with the trigeminal nucleus caudalis via neurotransmitters such as orexin.[citation needed]

Elevated levels of prolactin, secretion of which is regulated by the hypothalamus, seem to be associated with SUNCT attacks. Some patients with a pituitary tumor only experience attacks at night. These patients only exhibit higher levels of prolactin at night, even where hormone levels, including prolactin, were normal throughout the day.[7]

SUNCT is considered a primary headache (or condition), but can also occur as a secondary symptom of other conditions. However, a patient can only be diagnosed with SUNCT as a primary condition.[citation needed]

A pituitary tumor causes SUNCT as a secondary headache. Some patients with a pituitary tumor complain of short-lasting heachaches. Upon removal of the tumor, the symptoms of SUNCT may disappear permanently.[8]

Although it occurs very rarely, paranasal sinusitis can also cause secondary SUNCT. The symptoms of SUNCT in such cases can be removed permanently with endoscopic sinus surgery.[9]


SUNCT must be properly distinguished from cluster headaches, since cluster headaches also occur several times per day with separate attacks, and share some common symptoms. However, cluster headaches usually last longer (up to three hours), occur less often (three to five attacks per day), and do not accompany cranial autonomic symptoms. IHS standard criteria for the diagnosis of SUNCT specifically includes pain in the trigeminal division of the face, especially in the orbital region, often with cranial autonomic symptoms which last for relatively short periods of time (from five seconds to several minutes) up to 100 times per day. SUNCT is a major subset of SUNA,[10] which does not accompany cranial symptoms; complete separation between the two is inappropriate since SUNCT does not necessarily always accompany cranial autonomic signs. Exact statistical data is not available due to common mis-diagnosis, and setting up diagnostic criteria is important.[2]

The International Headache Classification established by the International Headache Society criteria for diagnosing SUNCT for therapeutic purposes is:[citation needed]

(i) Type of attack – Attacks of unilateral orbital, supraorbital, or temporal areas from stabbing or pulsating pain accompanied by ipsilateral conjunctival injection and lacrimation
(ii) Number of attacks per day – 3 to 200 attacks per day
(iii) Attack load in minutes per day – 5–240 seconds

Symptoms of SUNCT often lead to misdiagnosis as paroxysmal hemicrania, which is also categorized in the same group. Inefficiency of indomethacin usually indicates SUNCT over paroxysmal hemicrania.[11]

Misdiagnosis and indecisive diagnosis in the past has made it difficult to obtain accurate statistics about SUNCT. Proper diagnosis will broaden data availability and facilitate discovery of new treatment options and useful statistics.


As diagnostic criteria have been indecisive and its pathophysiology remains unclear, no permanent cure is available. Antiepileptic medications (membrane-stabilizing drugs) such as pregabalin, gabapentin, topiramate, and lamotrigine improve symptoms, but there is no effective permanent or long-term treatment for SUNCT.[12] However, a few short-term treatments are available and can relieve and possibly prevent some symptoms of attacks. Lamotrigine exhibits some long-term prevention and reduction in many patients; however, titration of dose is difficult due to adverse skin reactions. Topiramate also has preventive effects but it is accompanied by a high risk of severe side-effects for patients with a history of kidney stones, glaucoma, depression, or low body weight.[citation needed]

Intravenous lidocaine can abolish symptoms during its administration, or reduce frequency and duration of attacks. However, administration of intravenous lidocaine requires careful monitoring of ECG and blood pressure.[13] Methylprednisolone therapy shows some promise in short-term prevention of attacks, even though its mechanism of action is yet to be discovered.[14]

The calcium channel blocker verapamil is reported to be useful in alleviating symptoms (lower frequency and duration of attacks), even though some patients experience worsened symptoms.[11]

Various medications that are often used in other headache syndromes such as nonsteroidal anti-inflammatory drugs, acetaminophen, tricyclic antidepressants, calcium channel antagonists do not relieve the symptoms of SUNCT.

There have been attempts to alter oxygen supply during attacks to alleviate the symptoms since some of the headaches are caused by decreased oxygen supply; however, elevated blood oxygen level did not affect the symptoms.

The successful use of ayahuasca to treat SUNCT and relieve the symptoms for three weeks at a time has been reported.[15]

Researchers now[when?] focus on the administration of various combination of medications and therapies to treat symptoms of SUNCT.


In 1977, a 62-year-old male patient was the first to be diagnosed with SUNCT. The patient had experienced unilateral, mild pain in the ocular and periorbital areas since he was 30 years old. The patient started to experience more severe attacks after being struck by a fishing rod in the lower medial supraorbital area when he was 58 years old. The attacks could be provoked by mechanical stimuli and occurred more frequently with symptoms of conjuctival injection, lacrimation, and rhinorrhea. The definitive diagnosis and determination of the role of the trauma (fishing rod strike) could not be made until 10 years later when another similar case occurred. Conditions of the next case ruled out the possibility of SUNCT being a post-traumatic headache.[16]

Bad Brains singer H.R. has this disorder, as revealed by his wife.[17]

See also


  1. 1.0 1.1 1.2 Pomeroy, JL; Nahas, SJ (August 2015). "SUNCT/SUNA: A Review". Current Pain and Headache Reports. 19 (8): 38. doi:10.1007/s11916-015-0511-2. PMID 26092511. S2CID 29646696.
  2. 2.0 2.1 2.2 2.3 Cohen AS, Matharu MS, Goadsby PJ (October 2006). "Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) or cranial autonomic features (SUNA)—a prospective clinical study of SUNCT and SUNA". Brain. 129 (Pt 10): 2746–60. doi:10.1093/brain/awl202. PMID 16905753. Archived from the original on 2013-04-15. Retrieved 2022-08-31.
  3. Irimia P, Gállego-Pérez Larraya J, Martinez-Vila E (January 2008). "Seasonal periodicity in SUNCT syndrome". Cephalalgia. 28 (1): 94–6. doi:10.1111/j.1468-2982.2007.01434.x. PMID 17868283. S2CID 19188443.
  4. Cohen, A. S., M. S. Matharu, et al. (2006). "Functional MRI in SUNCT (Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing) and SUNA (Short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms) shows differential hypothalamic activation with increasing pain." Journal of Neurology, Neurosurgery, and Psychiatry 77(12): 041.
  5. Auer T, Janszky J, Schwarcz A, et al. (June 2009). "Attack-related brainstem activation in a patient with SUNCT syndrome: an ictal fMRI study". Headache. 49 (6): 909–12. doi:10.1111/j.1526-4610.2009.01348.x. PMID 19220497. S2CID 39514918.
  6. Goadsby PJ, Lipton RB (January 1997). "A review of paroxysmal hemicranias, SUNCT syndrome and other short-lasting headaches with autonomic feature, including new cases". Brain. 120 (Pt 1): 193–209. doi:10.1093/brain/120.1.193. PMID 9055807. Archived from the original on 2012-07-07. Retrieved 2022-08-31.
  7. Bosco D, Labate A, Mungari P, Vero S, Fava A (April 2007). "SUNCT and high nocturnal prolactin levels: some new unusual characteristics". J Headache Pain. 8 (2): 114–8. doi:10.1007/s10194-007-0370-2. PMC 3476135. PMID 17497264.
  8. Rocha Filho PA, Galvão AC, Teixeira MJ, et al. (June 2006). "SUNCT syndrome associated with pituitary tumor: case report". Arq Neuropsiquiatr. 64 (2B): 507–10. doi:10.1590/s0004-282x2006000300029. PMID 16917628.
  9. Choi JY, Seo WK, Kim JH, Oh K, Yu SW (2008). "Symptomatic SUNCT syndrome associated with ipsilateral paranasal sinusitis". Headache. 48 (10): 1527–30. doi:10.1111/j.1526-4610.2008.01243.x. PMID 19076651. S2CID 27878564. It is observed that TACs share some common phenotypes but have different pathophysiology.
  10. Tada Y, Ikuta N, Negoro K (2009). "Short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA)". Intern. Med. 48 (24): 2141–4. doi:10.2169/internalmedicine.48.2602. PMID 20009409.
  11. 11.0 11.1 Narbone MC, Gangemi S, Abbate M (June 2005). "A case of SUNCT syndrome responsive to verapamil". Cephalalgia. 25 (6): 476–8. doi:10.1111/j.1468-2982.2004.00876.x. PMID 15910576. S2CID 10190618.
  12. Pareja JA, Cuadrado ML, Caminero AB, Barriga FJ, Barón M, Sánchez-del-Río M (April 2005). "Duration of attacks of first division trigeminal neuralgia". Cephalalgia. 25 (4): 305–8. doi:10.1111/j.1468-2982.2004.00864.x. PMID 15773828. S2CID 42285100.
  13. Arroyo AM, Durán XR, Beldarrain MG, Pinedo A, García-Moncó JC (January 2010). "Response to intravenous lidocaine in a patient with SUNCT syndrome". Cephalalgia. 30 (1): 110–2. doi:10.1111/j.1468-2982.2009.01871.x. PMID 19438923. S2CID 9801531.
  14. Trauninger A, Alkonyi B, Kovács N, Komoly S, Pfund Z (June 2010). "Methylprednisolone therapy for short-term prevention of SUNCT syndrome". Cephalalgia. 30 (6): 735–9. doi:10.1111/j.1468-2982.2009.01971.x. PMID 19673911. S2CID 42721204.
  15. Rumpf, Pauline (26 August 2022). "Faute de solution médicale, l'ayahuasca m'a sauvé la vie". 20 Minutes. Archived from the original on 31 August 2022. Retrieved 31 August 2022.
  16. Sjaastad O, Russell D, Hørven I, et al. (1978). "Multiple, neuralgiform, unilateral headache attacks associated with conjunctival injection and appearing in clusters. A nosological problem". Proceedings of the Scandinavian Migraine Society. p. 31.
  17. Kreps, Daniel (March 16, 2016). "Bad Brains' H.R. Raising Money to Combat Headache Disorder". Rolling Stone. Archived from the original on 25 August 2016. Retrieved 21 October 2016.

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