Cluster Headache


Cluster Headache

Key Points:

  1. Cluster headaches are suffered by more men than women, but short lasting one-sided headache are still most likely cluster headaches even in women.
  2. Correct diagnosis of cluster headaches require awareness of short lasting headaches with red eye, tearing, runny nose and/or other associated symptoms occurring on one side of the head in a series over weeks.
  3. If this is your first Cluster series an MRI with contrast including MRA of carotids and vertebrals is essential.
  4. Control requires both acute and preventative treatments. 100% O2 by mask or injectable sumatriptan or DHE with an early course of steroids and verapamil daily throughout are most effective.
  5. Followup is critical to minimize disability and optimize treatment benefits and safety.

Cluster headaches (CH) are often said to be the most painful of all headaches. They have been described as "boring," bearing, burning," "like a hot poker in the eye," and as "suicide headaches." The age of onset of CH is most often between 20 and 40, and they are more common in men than women at a ratio of 2.1. For many years, that ratio was stated to be 3:1. Researchers theorize that women have long been misdiagnosed because CH were thought to be so predominantly found in men. CH and smoking often occur together. Alcohol is rarely tolerated anytime during periods of CH.

Numerous terms have previously been used to refer to cluster headaches: ciliary neuralgia, erythro-melalgia of the head, erythroprosopalgia of Bing, hemicrania angioparalytica, hemicrania neuralgiformis chronica, histaminic cephalalgia, Horton’s headache, Harris-Horton’s disease, migrainous neuralgia (of Harris), petrosal neuralgia (of Gardner). Now CH is known as the most common trigeminal autonomic cephalalgia (TAC) type of primary headache or headaches involving activity of the 5th cranial nerve with highly frequent cranial autonomic symptoms (CAS) (see below).

Symptoms of Cluster Headache
Cluster headaches are attacks of severe pain lasting 15-180 minutes and occurring from once every other day up to eight times in one day; averaging 2 per day over typically 4-6 weeks then entirely disappearing for 6-12 months.

The pain is:

  • severe
  • unilateral
  • orbital (near the orbit, the bone framing the eye), supraorbital (above the orbit), temporal (at the temple), or a combination of those sites and sometimes more towards the back of the head.

These attacks also include one or more cranial autonomic symptoms (CAS) on the same side as the pain (ipsilaterally):

  • red eye (conjunctival injection - forcing of fluid into the conjuctiva, the mucous membrane that lines the eyelids)
  • eyelid swelling (edema)
  • forehead and facial sweating
  • tearing (lacrimation)
  • abnormal small size of the pupil (miosis)
  • nasal congestion
  • runny nose (rhinorrhea)
  • drooping eyelid (ptosis)

Another typical feature is that most cluster headache patients are restless or agitated during attacks. Unlike migraineus they find it hard to be still and rarely lay down. Cluster sufferers characteristically pace the floor during attacks.

The Diagnosis of CH
The term CH comes from the recurrence of attacks usually in series (cluster periods) lasting for weeks or months separated by remission periods usually lasting months or years. Cluster headaches are diagnosed as "episodic" when the attacks occur in periods lasting 7 days to 1 year separated by pain-free periods lasting 1 month or longer. In "chronic" cluster headaches, attacks occur for more than 1 year without remission or with remissions lasting less than 1 month. More than 80% have the episodic CH form.

According to the strict criteria of the International Classification of Headache Disorders, (ICHD-2004) at least 5 attacks meeting the following are required:

  • At least 5 attacks fulfilling the following criteria
  • Severe or very severe unilateral orbital, supraorbital and/or temporal pain lasting
    15–180 minutes if untreated
  • Headache is accompanied by at least one of the following:
    • Red eye or tearing on the side of the headache
    • Nasal congestion or runny nose on the side of the headache
    • Eyelid swelling on the side of the headache
    • Forehead and facial sweating on the side of the headache
    • Small pupil or eyelid droop on the side of the headache
    • a sense of restlessness or agitation
  • Attacks have a frequency from one every other day to 8 per day

Many migraineurs with frequent repeat or return (recurrence) of their migraine are given an incorrect diagnosis of CH. This is in large part due to the lack of information about the correct diagnosis of CH. Cluster headaches last without treatment much less than 4 hours on average. Migraine lasts much more than 4 hours on average in the age group typically diagnosed with CH. That is, young migraineurs can have very short migraine headache episodes. Mis-labeling is in part is due to the fact that cranial autonomic symptoms occur in both disorders. In this case the length of headache matter but may not e adequately considered. Lai et al identified one or more CAS in 56% of migraineurs and 95% of cluster headache patients. In general, migraineurs had less number of features; they were less prominent or less consistently related to attacks and more likely to be on both sides compared with patients with cluster headache. Besides length of headache and frequency and intensity of cranial autonomic symptoms a third important clinical difference between migraine and CH, as well as other TACs, is location of headache and CAS. Specifically, that cluster headaches are one sided (unilateral) typically without changing sides of the head from one attack to another. Migraine typically changes sides, although a side preference is common. Cranial autonomic symptoms and light and noise sensitivity are on the same side of headache in CH, but not in migraine.

Perhaps less of an issue in some countries than others, nasal stuffiness or runny nose or facial pain location should not be used to indicate cranial sinus pathology. Cluster patients will have sinus imaging abnormalities due to activity of nerves to these areas which will result in unnecessary and possibly harmful procedures in CH. Aura does occur in cluster headache but is quite uncommon. This suggests an overlap syndrome with migraine or possibly two headache types.

The correct diagnosis of CH requires awareness of one-sided without side shifting short lasting headaches with CAS and associated symptoms occurring in series.

Correct Diagnosis
Headache Specialists caution that care be taken to arrive at the proper diagnosis. At times it can be difficult to differentiate between migraine with and without aura, CH and other TAC types. Migraine with prominent autonomic features, CH with aura, paroxysmal hemicrania, short lasting unilateral neuralgiform headaches with red eye and tearing (conjunctival injection and tearing) (SUNCT/SUNA) and hemicrania continua (one sided constant headache with mild CAS) are several examples. It wouldn’t matter if treatment were the same; but treatment and response vary considerably. It truly matters. It is essential that the diagnosis be as definitive and correct as possible, so your history really does matter. Diagnosis may require imaging as discussed next. If the provider making the diagnosis is hesitant about it, definitely seek a second opinion from another provider. Since features and associations of CH are not well known to many providers, seeing a headache specialist is advisable when possible. You may achieve best advice if this provider is certified by the United Council of Neurological Subspecialties (UCNS). See Find a Healthcare Professional. It is also important to continue medical treatment as advised by your doctor and not skip follow-up appointments. Upon correct diagnosis CH sufferers should consider having medical identification of some kind on their person as many providers will not recognize this disorder. This will alert them to refresh what they know.

There are no diagnostic tests to confirm CH. Diagnosis is accomplished by reviewing personal and family medical history, especially headache, considering associated symptoms, and an examination. Rare brain or cranial artery abnormality detected only by brain imaging can cause a CH. Brain imaging with MRI with and without (IV) contrast is necessary at initial diagnosis or sometime during the course if atypical or without response to treatment. Avoid contrast with proven allergy or kidney function less than 30 GFR (unlikely due to age, gender of most patients). Remember: response to a treatment does not tell you whether the diagnosis is correct or not. Imaging is at times critical.

Cluster headache can be successfully treated in most cases with sufficient quality of life by individualizing acute and preventive drug treatment.

Acute treatment:
The most commonly used therapies to shorten or abort a cluster attack are:

  • 100% oxygen (O2) by mask used sitting up
  • sumatriptan (Imitrex, Imigran) nasal spray or in the skin (subcutaneous) injection
  • DHE-45 nasal spray (Migranal) or injection
  • zolmitriptan (Zomig) nasal spray

All three are found in research trials to be effective. Cluster typically increases rapidly to severe intensity over just minutes. For treatment to shorten attacks effective acute treatment must be used just as rapidly. Insurance often limits access to any/all of these options. Providers must often educate both patient and insurance about CH. Often smaller doses of drug provide the same benefit but more treatments to help address this deficiency. Access to all forms of acute therapy or at least O2 and one drug are essential.

The most commonly used preventive medications are:

  • verapamil
  • steroids (commonly prednisone)
  • lithium
  • divalproex sodium (Depakote, Depakote ER)
  • topiramate (Topamax)
  • melatonin

These agents are used by clinical tradition without research trial data. Doses of verapamil are typically double or more than that used for other disorders. The greatest preventive error is typically not using verapamil to its limitation. Experts recommend an EKG to monitor QTc intervals. Obtain an EKG for every dose increase over 480mg and for any continuing dose; every 6 months for safety.

Disability and Prognosis
Cluster headache is severely disabling while active. Because of the severity of pain and frequency of disturbing sleep CH is often more debilitating than other primary headache disorders. Cluster headache sufferers may injure themselves when trying to stop the pain. A concern about stroke risk exists mainly due to the high frequency of smoking and other cardiovascular risk factors present in many older CH patients with the use of artery narrowing (vasoconstricting) drugs. Attention to reduction of stroke risk factors is appropriate. As a CH patient if others are not educated about CH, it is particularly important that efforts be made to inform them.

Cluster headache is one type of trigeminal autonomic cephalgia (TAC). It is one of the most severe intensity and devastating pain syndromes. As with other forms of headache, it is necessary to have an accurate diagnosis and effective treatment plan. This requires use of that treatment as early as possible typically best with 100% oxygen or injection. Some find a nasal spray adequate. A Medical ID Alert for CH may be of benefit. Severe CH fortunately does not typically require seeking emergency care. Unfortunately, ED/ERs often treat cluster headache with narcotics. Access to a headache specialist is important. Once diagnosed with CH, it is important as with any headache type to minimize the frequency of attacks through optimal prevention. Also contact your provider if your symptoms or pattern change. Without consulting a knowledgeable provider, it's impossible to be sure that new symptoms or changes in pattern are attributable to CH, and that no other condition is present. Cluster headache is reason to seek and request the best care available and then its necessary to follow that advice. 

"The International Classification of Headache Disorders, 2nd Edition." Cephalalgia 24 (s1). doi: 0.1111/j. 1468-2982.2003.00824.x

Lai T-H, Fuh J-L, Wang S-J. Cranial autonomic symptoms in migraine: characteristics and comparison with cluster headache. J Neurol Neurosurg Psychiat 2009;80:1116–1119.

Stephen D. Silberstein, MD; Alan Stiles, DMD; William B Young, MD; Todd D. Rozen, MD. "An Atlas of Headache." Parthenon Publishing, 2002.

Randolph W. Evans, Nina T. Mathew. "Handbook of Headache, Second Edition." Philadelphia: Lipincott Williams & Wilkins. 2005.

Young, William B., MD; Silberstein, Stephen D., MD. "Migraine and Other Headaches." Ney York: AAN Press. 2004.

Stephen D. Silberstein, MD, Richard B. Lipton, MD, and Donald J. Dalessio, MD. "Wolff's Headache and Other Head Pain," seventh edition. Oxford University Press, 2001.

Edited by Frederick R. Taylor, MD August 14, 2010

Cluster Headaches - The Basics. Written by Teri Robert and published on Copyright 2004 - Present. Teri Robert. All rights reserved. Last updated February 27, 2010. Medical review by John Claude Krusz, PhD, MD. 



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