Editing Cluster headache (section)

==Signs and symptoms==
Cluster headaches are recurring bouts of severe unilateral headache attacks.<ref name=Beck>{{cite journal |vauthors=Beck E, Sieber WJ, Trejo R |title=Management of cluster headache |journal= American Family Physician|volume=71 |issue=4 |pages=717–24 |date=February 2005 |pmid=15742909 |url=http://www.aafp.org/afp/2005/0215/p717.html |type=Review |url-status=live |archive-url=https://web.archive.org/web/20151113055721/http://www.aafp.org/afp/2005/0215/p717.html |archive-date=13 November 2015 }}</ref><ref name="pmid16628535">{{cite journal |doi=10.1055/s-2006-939925 |pmid=16628535 |title=Diagnosis and Treatment of Cluster Headache |journal=Seminars in Neurology |volume=26 |issue=2 |pages=242–59 |year=2006 |last1=Capobianco |first1=David |last2=Dodick |first2=David |s2cid=260319925 }}</ref> The duration of a typical cluster headache ranges from about 15 to 180 minutes.<ref name=AFP2013/> About 75% of untreated attacks last less than 60 minutes.<ref name=EM2009>{{cite journal |doi=10.1016/j.emc.2008.09.005 |pmid=19218020 |pmc=2676687 |title=Diagnosis and Management of the Primary Headache Disorders in the Emergency Department Setting |journal=Emergency Medicine Clinics of North America |volume=27 |issue=1 |pages=71–87, viii |year=2009 |last1=Friedman |first1=Benjamin Wolkin |last2=Grosberg |first2=Brian Mitchell }}</ref> However, women may have longer and more severe cluster headaches.<ref name=CHandM2019>{{cite journal |vauthors=Vollesen AL, Benemei S, Cortese F, Labastida-Ramírez A, Marchese F, Pellesi L, Romoli M, Ashina M, Lampl C, ((School of Advanced Studies of the European Headache Federation (EHF-SAS)))|title=Migraine and cluster headache - the common link. |date=2018 |journal= [[The Journal of Headache and Pain]]|volume=19 |issue=1 |page=89 |doi=10.1186/s10194-018-0909-4|pmid=30242519 |pmc=6755613 |doi-access=free }}</ref>

The onset of an attack is rapid and typically without an [[Aura (symptom)|aura]]. Preliminary sensations of pain in the general area of attack, referred to as "shadows", may signal an imminent cluster headache, or these symptoms may linger after an attack has passed, or between attacks.<ref>{{cite journal |doi=10.1177/0333102410372423 |pmid=20974600 |title=Interictal pain in cluster headache |journal=Cephalalgia |volume=30 |issue=12 |pages=1531–4 |year=2010 |last1=Marmura |first1=Michael J |last2=Pello |first2=Scott J |last3=Young |first3=William B |s2cid=153838 }}</ref> Though cluster headaches are strictly unilateral, there are some documented cases of "side-shift" between cluster periods,<ref>{{cite journal |doi=10.1007/s10194-009-0129-z |pmid=19495933 |pmc=3451747 |title=Lateralization in cluster headache: A Nordic multicenter study |journal=[[The Journal of Headache and Pain]] |volume=10 |issue=4 |pages=259–63 |year=2009 |last1=Meyer |first1=Eva Laudon |last2=Laurell |first2=Katarina |last3=Artto |first3=Ville |last4=Bendtsen |first4=Lars |last5=Linde |first5=Mattias |last6=Kallela |first6=Mikko |last7=Tronvik |first7=Erling |last8=Zwart |first8=John-Anker |last9=Jensen |first9=Rikke M. |last10=Hagen |first10=Knut }}</ref> or, rarely, simultaneous (within the same cluster period) bilateral cluster headaches.<ref>{{cite journal |pmid=11839832 |title=Cluster headache: A prospective clinical study with diagnostic implications |journal=Neurology |volume=58 |issue=3 |pages=354–61 |year=2002 |last1=Bahra |first1=A |last2=May |first2=A |last3=Goadsby |first3=PJ |doi=10.1212/wnl.58.3.354|s2cid=46463344 }}</ref>

===Pain===
The pain occurs only on one side of the head, around the eye, particularly behind or above the eye, in the temple. The pain is typically greater than in other headache conditions, including [[migraine]]s, and is usually described as burning, stabbing, drilling or squeezing.<ref name="MehtaMaloney2011">{{cite book|author1=Noshir Mehta|author2=George E. Maloney|author3=Dhirendra S. Bana|author4=Steven J. Scrivani|title=Head, Face, and Neck Pain Science, Evaluation, and Management: An Interdisciplinary Approach|url=https://books.google.com/books?id=hgzeUKoeaTcC&pg=PT199|date=20 September 2011|publisher=John Wiley & Sons|isbn=978-1-118-20995-0|page=199|url-status=live|archive-url=https://web.archive.org/web/20170214214959/https://books.google.com/books?id=hgzeUKoeaTcC&pg=PT199|archive-date=14 February 2017}}</ref> While suicide is rare, those with cluster headaches may experience suicidal thoughts (giving the alternative name "suicide headache" or "suicidal headache").<ref name=Rob2013/><ref>{{cite book|title=The 5-Minute Sports Medicine Consult|date=2012|publisher=Lippincott Williams & Wilkins|isbn=9781451148121|page=87|edition=2|url=https://books.google.com/books?id=-LOm9enAxQ8C&pg=PA87|url-status=live|archive-url=https://web.archive.org/web/20170910172156/https://books.google.com/books?id=-LOm9enAxQ8C&pg=PA87|archive-date=10 September 2017}}</ref>

[[Peter Goadsby|Dr. Peter Goadsby]], Professor of Clinical Neurology at University College London, a leading researcher on the condition has commented: {{blockquote|"Cluster headache is probably the worst pain that humans experience. I know that's quite a strong remark to make, but if you ask a cluster headache patient if they've had a worse experience, they'll universally say they haven't. Women with cluster headache will tell you that an attack is worse than giving birth. So you can imagine that these people give birth without anesthetic once or twice a day, for six, eight, or ten weeks at a time, and then have a break. It's just awful."<ref>{{cite web|author=Goadsby P, Mitchell N|year=1999|title=Cluster Headaches|publisher=[[Australian Broadcasting Corporation]] |url=https://www.abc.net.au/rn/talks/8.30/helthrpt/stories/s42434.htm |url-status= dead|archive-url=https://web.archive.org/web/20110922070249/https://www.abc.net.au/rn/talks/8.30/helthrpt/stories/s42434.htm|archive-date=22 September 2011}}</ref>}}

===Other symptoms===
The typical symptoms of cluster headache include grouped occurrence and recurrence (cluster) of headache attack, severe unilateral orbital, supraorbital and/or temporal pain. If left untreated, attack frequency may range from one attack every two days to eight attacks per day.<ref name=AFP2013/><ref name=IHS/> Cluster headache attack is accompanied by at least one of the following autonomic symptoms: [[Ptosis (eyelid)|drooping eyelid]], [[miosis|pupil constriction]], redness of the [[conjunctiva]], [[lacrimation|tearing]], [[rhinorrhea|runny nose]] and less commonly, [[facial blushing]], swelling, or sweating, typically appearing on the same side of the head as the pain.<ref name=IHS/> Similar to a migraine, sensitivity to light ([[photophobia]]) or noise ([[hyperacusis]]) may occur during a cluster headache. Nausea is a rare symptom although it has been reported.<ref name=Beck/>

Restlessness (for example, pacing or rocking back and forth) may occur. Secondary effects may include the inability to organize thoughts and plans, physical exhaustion, confusion, agitation, aggressiveness, depression, and anxiety.<ref name="Rob2013"/>

People with cluster headaches may dread facing another headache and adjust their physical or social activities around a possible future occurrence. Likewise they may seek assistance to accomplish what would otherwise be normal tasks. They may hesitate to make plans because of the regularity, or conversely, the [[Predictability|unpredictability]] of the pain schedule. These factors can lead to generalized [[anxiety disorder]]s, [[panic disorder]],<ref name="Rob2013"/> serious [[depressive disorder]]s,<ref>{{cite journal |doi=10.1177/0333102412469738 |pmid=23212294 |title=Cluster headache is associated with an increased risk of depression: A nationwide population-based cohort study |journal=Cephalalgia |volume=33 |issue=3 |pages=182–9 |year=2012 |last1=Liang |first1=Jen-Feng |last2=Chen |first2=Yung-Tai |last3=Fuh |first3=Jong-Ling |last4=Li |first4=Szu-Yuan |last5=Liu |first5=Chia-Jen |last6=Chen |first6=Tzeng-Ji |last7=Tang |first7=Chao-Hsiun |last8=Wang |first8=Shuu-Jiun |s2cid=23184973 |doi-access=free }}</ref> social withdrawal and isolation.<ref>{{cite journal |doi=10.1111/j.1468-2982.2007.01330.x |pmid=17459083 |title=Burden of Cluster Headache |journal=Cephalalgia |volume=27 |issue=6 |pages=535–41 |year=2016 |last1=Jensen |first1=RM |last2=Lyngberg |first2=A |last3=Jensen |first3=RH |s2cid=38485245 }}</ref>

Cluster headaches have been recently associated with obstructive [[sleep apnea]] comorbidity.<ref>{{cite journal |title=Right-to-left shunt and obstructive sleep apnea in cluster headache |journal=Neurology & Neurosc. |volume=1 |issue=1 |pages=1–3 |year=2020 |last1=Tabaee D. |first1=Payam |last2=Rizzoli |first2=P |last3=Pecis |first3=M |url=https://www.sciencexcel.com/articles/Right-to-left%20shunt%20and%20obstructive%20sleep%20apnea%20in%20cluster%20headache |access-date=22 January 2021 |archive-date=24 October 2020 |archive-url=https://web.archive.org/web/20201024174835/https://www.sciencexcel.com/articles/Right-to-left%20shunt%20and%20obstructive%20sleep%20apnea%20in%20cluster%20headache |url-status=live }}</ref>

===Recurrence===
Cluster headaches may occasionally be referred to as "alarm clock headache" because of the regularity of their recurrence. Cluster headaches often awaken individuals from sleep.  Both individual attacks and the cluster grouping can have a metronomic regularity; attacks typically strike at a precise time of day each morning or night. The recurrence of headache cluster grouping may occur more often around [[solstice]]s, or seasonal changes, sometimes showing circannual periodicity. Conversely, attack frequency may be highly unpredictable, showing no periodicity at all. These observations have prompted researchers to speculate an involvement or dysfunction of the hypothalamus. The hypothalamus controls the body's "biological clock" and [[circadian rhythm]].<ref>{{cite journal |doi=10.1017/S0317167100001694 |pmid=11858532 |title=Cluster Headache: Evidence for a Disorder of Circadian Rhythm and Hypothalamic Function |journal=The Canadian Journal of Neurological Sciences |volume=29 |issue=1 |pages=33–40 |year=2014 |last1=Pringsheim |first1=Tamara |doi-access=free }}</ref><ref>{{cite journal |doi=10.1046/j.1526-4610.2003.03055.x |pmid=12603650 |title=Clinical, Anatomical, and Physiologic Relationship Between Sleep and Headache |journal=Headache: The Journal of Head and Face Pain |volume=43 |issue=3 |pages=282–92 |year=2003 |last1=Dodick |first1=David W. |last2=Eross |first2=Eric J. |last3=Parish |first3=James M. |s2cid=6029272 }}</ref> In episodic cluster headache, attacks occur once or more daily, often at the same time each day for a period of several weeks, followed by a headache-free period lasting weeks, months, or years. Approximately 10–15% of cluster headaches are [[Chronic (medicine)|chronic]], with multiple headaches occurring every day for years, sometimes without any remission.<ref name="NHS">{{cite web |url=https://www.nhs.uk/conditions/cluster-headaches/ |title=Cluster headaches:Pattern of attacks |author=<!--Not stated--> |date=22 May 2017 |website=NHS |publisher=Gov.UK |access-date=13 December 2018 |archive-date=20 June 2019 |archive-url=https://web.archive.org/web/20190620122856/https://www.nhs.uk/conditions/cluster-headaches/ |url-status=live }}</ref>

In accordance with the International Headache Society (IHS) diagnostic criteria, cluster headaches occurring in two or more cluster periods, lasting from 7 to 365 days with a pain-free [[Remission (medicine)|remission]] of one month or longer between the headache attacks may be classified as episodic. If headache attacks occur for more than a year without pain-free remission of at least three months, the condition is classified as chronic.<ref name=IHS>{{cite web |url= https://ichd-3.org/3-trigeminal-autonomic-cephalalgias/3-1-cluster-headache/3-1-2-chronic-cluster-headache/ |title= IHS Classification ICHD-3 3.1.2 Cluster headache |publisher= The International Headache Society |access-date= 2024-02-08 |archive-date= 8 February 2024 |archive-url= https://web.archive.org/web/20240208085008/https://ichd-3.org/3-trigeminal-autonomic-cephalalgias/3-1-cluster-headache/3-1-2-chronic-cluster-headache/ |url-status= live }}</ref>
Chronic cluster headaches both occur and recur without any remission periods between cycles; there may be variation in cycles, meaning the frequency and severity of attacks may change without predictability for a period of time. The frequency, severity, and duration of headache attacks experienced by people during these cycles varies between individuals and does not demonstrate complete remission of the episodic form. The condition may change unpredictably from chronic to episodic and from episodic to chronic.<ref>{{cite journal |doi=10.1007/s11916-002-0026-5 |pmid=11749880 |title=What predicts evolution from episodic to chronic cluster headache? |journal=Current Pain and Headache Reports |volume=6 |issue=1 |pages=65–70 |year=2002 |last1=Torelli |first1=Paola |last2=Manzoni |first2=Gian Camillo |s2cid=37173661 }}</ref>