Diagnosing Misdiagnosis: Understanding Cluster Headache delay

Diagnosing Misdiagnosis: Understanding Cluster Headache delay

Waiting. It has always been a difficult thing for humans to bear. In today’s hurried world of instant Internet connections, streaming movies at our fingertips, and same-day deliveries, waiting becomes increasingly difficult, even for the most patient among us.

For many, a challenge that’s probably equal in difficulty is moving ahead and getting significantly down a path only to find it’s the wrong one.

Now, if you can imagine adding to your wait or your wrong turn the burden of agonizing physical pain, you’ll begin to get a picture of the experience of many patients that suffer from cluster headache, a severe headache disorder described as being 10 out of 10 in severity.1 While it’s rare, affecting just one adult in 1,000, cluster headache is one of the most severe, painful and disabling kinds of headache. It leaves many sufferers unable to fully participate in life, work, or activities with family and friends.

In recent years, research has shown that many who suffer from severe headache without realizing that it’s actually cluster headache, commonly experience substantial delays—sometimes for years—in getting the correct diagnosis. For some of them, the delay is partially due to being inadvertently sidetracked by one or more misdiagnoses of their condition. With others, the delay is due to having received no diagnosis at all from their healthcare professionals.

These problems amount to patients going for lengthy periods without appropriate treatment for cluster headache, which headache experts confirm needs rapid diagnosis, due to the intensity of attacks and the disability they cause.2

The good news is that recent research is shedding light on diagnostic delays and misdiagnosis in cluster headache, as well as some of the reasons it happens.

Diagnosis: The way things should be and the way they are
Even though cluster headache is rare, when it comes to diagnosis, experts say that it has clear-cut features that should make it “easily recognizable.”2,3 It’s characterized by recurrent attacks of pain on one side of the head in and around the eye socket and the temple. Lasting 15 to 180 minutes each, cluster attacks are accompanied by at least one of the following involuntary symptoms of the autonomic nervous system on the same side of the face as the pain:

  • Eye redness and/or excessive tearing
  • Nasal congestion and/or runny nose
  • Swollen, inflamed eyelids
  • Forehead and facial sweating/flushing
  • A sensation of fullness in the ear
  • Constriction of the pupil, and/or
  • Drooping of the upper eyelid


Despite these established international criteria, cluster headache is frequently misdiagnosed, not treated according to medically-established recommendations, and on average, takes years before patients are diagnosed for the condition.

In a study published in 2014 in which 75 cluster headache patients were seen in five Spanish headache clinics, a team headed by Dr. Margarita Sanchez del Rio found that it took their study subjects an average of 4.9 years from the onset of their attacks until they received a cluster headache diagnosis. In the same article, they documented diagnostic delays from studies across Europe ranging from 2.6 years in the United Kingdom to 11 years in Norway, with subjects consulting an average of 4 physicians before receiving the correct diagnosis. Two extensive surveys in the U.S., also referenced in the article, found an average diagnostic delay of 6 years, with patients consulting an average of 4.3 physicians before diagnosis.3

Another study published in 2014 by Dr. Cristina Voiticovschi-losob and her colleagues looked at 144 patients from Italy and Eastern Europe and found an average diagnostic delay of 5.3 years per patient, although for a third of them, the average was more than 12 years. Some patients in this study had seen 2 or 3 physicians prior to being diagnosed, for an average of 2.6 per patient.2

What’s the holdup? Contributors to diagnostic delays
With patients enduring such extreme pain and suffering, it may be difficult for the average person to understand why there are such long delays between the onset of cluster attacks and getting an accurate diagnosis. There are many factors that can impact the time it takes to get to an accurate diagnosis of cluster headache (CH). First, we should recognize that there are two parties primarily involved and working together in the diagnostic process: the doctor and the patient. To better understand the diagnostic process in cluster headache, it can help to look at factors related to the doctor’s role as well as those related to the patient’s role.

In looking at doctor-related factors, Dr. Voiticovschi-losob notes that diagnostic delay due to medical misdiagnosis “remains one of the biggest problems for cluster headache patients.”2 While explaining that headache specialists or general neurologists are “in fact, usually the ones that first diagnose the disease,” Dr. Voiticovschi-losob points out that, in her team’s study, “The physicians most frequently consulted at the onset of disease, after neurologists, were primary care physicians, ENT specialists, dentists and various non-medical therapists.”

Considering the rarity of the condition, it’s understandable that these healthcare providers “may be less familiar with CH, and this might indeed help to explain the diagnostic delays reported,” she adds.2

With an eye to caution, some doctors can also contribute to diagnostic delay by conducting additional tests, according to Dr. Voiticovschi-losob. Though presented with symptoms of a primary headache, which is a headache caused by the condition itself (e.g. cluster is a primary headache), these providers continue searching for a headache caused by another condition, such as sinus headache.

“Physicians faced with a cluster-like picture and not wanting to risk missing a secondary headache may be prompted to prescribe several, sometimes unnecessary, investigations,” she says, adding that, in her study, those most often prescribed included brain MRI, brain CT scans, skull X-ray, EEGs, and cervical spine X-ray. Depending on local protocols, these tests may be spread over a period of time. This approach, she says, “increases the time to cluster headache diagnosis.”2

Whether by choice or simply for lack of information, patients can also add to the delay between the onset of cluster headache and its diagnosis.

Considering the extreme severity of cluster headache pain, it seems unimaginable to many of us that someone could suffer these kinds of attacks and not consult a physician. Nevertheless, this response is a very real patient-related factor that contributes to diagnostic delay. While the majority in the Voiticovschi-losob study had seen a doctor at the onset of their attacks, nearly a quarter of patients (23.6%) had not sought medical help, thereby “giving rise to a ‘patient delay’ in the diagnosis.”2

It’s possible that gaps in the information patients have about medical resources can also contribute to the time it takes for diagnosis. Regardless of how patients acquire their medical information, Dr. Voiticovschi-losob found that nearly 1 in 5 (18%) patients in the study was not even aware of the existence of specialist headache centers. This is unfortunate, since headache specialists, as we noted earlier, are among the physicians most likely to first diagnose cluster headache.2

Misdiagnosis: The biggest contributor
Not only are lengthy diagnostic delays a difficult reality in cluster headache but, as we’ve noted, the condition is frequently misdiagnosed, and diagnosis delays due to misdiagnosis are a substantial obstacle for patients.

It’s essential to establish that misdiagnosis of this rare condition is not primarily about physician capability, but instead about the need for continuous medical education of physicians. This conclusion and call to action is widely espoused by headache experts.

Dr. Sanchez del Rio says, for example, that misdiagnosis and unrecognized cluster headache both call for better “education in the diagnosis of the main primary headaches.”3 Dr. Voiticovschi-losob emphasizes the need to improve specialist education while also ensuring continuous medical education for general neurologists, primary care physicians, ENT specialists and dentists, given that the latter group “are often the cluster headache patient’s first point of call.”2 And Drs. Paolo Martelletti and Dimos Mitsikostas conclude a 2015 editorial by asserting that more widespread physician education “should lead to an earlier diagnosis and a more adequate treatment” of cluster headache, which after all, is the ultimate aim.4

Scale of misdiagnosis with cluster headache
When looking at the actual figures, it’s common to find that 50 to 75 percent of patients receive at least one misdiagnosis of their condition before accurately being diagnosed with cluster headache.

In the Sanchez del Rio study of 75 patients in Spain, only 15 percent of cluster headache patients received a correct diagnosis on their first physician visit. Meanwhile 28 percent had never received a specific diagnosis, and 57 percent had been misdiagnosed with an average rate of 2.1 alternative diagnoses per patient.3

In the Voiticovschi-losob study of 144 cluster patients in Italy and Eastern Europe, more than three quarters of patients (75.6%) were misdiagnosed at least once, and of those, 29.1 percent were misdiagnosed two or three times.2

In both studies, the most frequent misdiagnoses were migraine, trigeminal neuralgia, and sinus headache from sinusitis. A deeper look at some of these misdiagnoses can provide insight as to how misdiagnosis can be so common.

Diagnosing misdiagnosis: Understanding misses on cluster headache
While the path to reducing the rate of misdiagnosis in the long run may be continuous medical education of physicians, looking at some of the characteristics that other headache disorders share in common with cluster headache can provide insights about misdiagnosis that may be helpful in the short run.

Sinus headache due to sinusitis is a common misdiagnosis of cluster headache in clinical practice. According to Dr. Sanchez del Rio, this mix-up can happen because the location of the pain in both conditions is similar. Both types of headache also exhibit the cranial autonomic symptoms (e.g., tearing).

In our previous post on the changing gender ratio in cluster headache, we discussed how it’s common for women to be misdiagnosed at a higher rate than men. In fact, in a Danish study of 351 patients published earlier this year by Dr. Nunu Lund and colleagues, significantly more women than men had been misdiagnosed at some point (61.1% vs. 45.5%).5

Equally interesting is that the misdiagnosis of cluster headache in women happens most often with migraine,5,6 which may be driven by several factors:

  • First, it’s well known that migraine is more common in females while cluster headache is commonly identified as a male disorder.
  • Cluster headache also shares a number of symptoms in common with migraine, including nausea, vomiting, photophobia (light sensitivity), phonophobia (sound sensitivity), and even aura. These symptoms have not only been described traditionally as “migrainous” but they’re also not listed on the International Headache Society’s list of cluster headache-specific criteria.6
  • Another complicating factor is that cluster headache was regarded as a variant of migraine for many years.7

These common examples of misdiagnosing cluster headache as migraine or sinusitis can help us better understand some of the challenges of diagnosing this disorder, especially considering its rarity.

Diagnosis makes the difference: Getting to treatment with cluster headache
Despite the large margin of misdiagnosis with this condition, there is hope for those people living with cluster headache.

Dr. Karl Ekbom, the author of a large Swedish study on cluster headache, suggested that, with the decline of the male:female ratio in the condition, the increasing recognition of it in women, and a body of medical literature on cluster headache that has expanded substantially since the 1960s, it’s possible that the diagnosis of cluster headache in women could actually be improving.7 If that were the case, could these signs also point to the possibility that diagnosis in general is improving?

And, when patients finally do receive a correct diagnosis of cluster headache, it can make a substantial difference in the treatment prescribed. Researchers in the Voiticovschi-losob study documented how treatment improved for the study subjects after their physicians had accurately diagnosed them with cluster headache.2

Patients with cluster headache typically use abortive or acute treatments for rapid pain relief during an attack and/or preventive treatments for blocking attacks before they begin. Researchers found that only 18% of patients experiencing symptoms were prescribed one of the abortive treatments recommended by international medical guidelines, including 17% having been prescribed triptans and the other 1% having received oxygen.8 However, after being correctly diagnosed, those proportions jumped dramatically to 52.7% and 22% respectively.

And, researchers observed that only 23% of patients were placed on some kind of preventive treatments for cluster headache. After diagnosis, the proportion placed on preventive treatments jumped to 89%.2

The patience of patients: Hurry up and wait or get the ball rolling?
With the diagnostic delays and misdiagnosis in cluster headache documented by medical research, it’s encouraging to know that headache experts are unified in promoting broader physician education about this painful and disabling disorder.

For patients, is simply waiting to receive a correct diagnosis all that can be done, or is there something more that patients can do to move the process along?

First, if you or someone you care about is suffering from severe headache, make sure you’re not contributing to the “patient delay” described earlier. If you’re part of that quarter of patients that has not yet sought medical assistance, realize that there’s help to be had. Don’t try to tough out something that may not be going away. Get help. See a physician.

If, however, you have seen a doctor for your severe headache but you’ve either not received a diagnosis or your treatment is not effective, you can ask your doctor if you should see a specialist. Visiting a neurologist or headache specialist to find out about the possibility of cluster headache may be the fastest path to getting an accurate diagnosis, the appropriate treatment, and your life back on track.

Enjoyed this article? Don’t forget to share.



  1. Mitsokostas, et al. Refractory chronic cluster headache: a consensus statement on clinical definition from the European Headache Federation. The Journal of Headache and Pain. 2014; 15:79
  2. Voiticovshi-losob, et al. Diagnostic and therapeutic errors in cluster headache: a hospital-based study. The Journal of Headache and Pain 2014, 15:56
  3. Sánchez del Rio, et al. Errors in Recognition and Management are Still Frequent in Patients with Cluster Headache. Eur Neurol 2014;72:209–212
  4. Martelletti and Mitsikostas. Cluster headache: a quasi-rare disorder needing a reappraisal. The Journal of Headache and Pain. 2015;16:59
  5. Lund, et al. Chronobiology differs between men and women with cluster headache, clinical phenotype does not. Neurology. 2017 Mar 14;88(11):1069-1076.
  6. Rozen TD, Fishman RS. Cluster headache in the United States of America: demographics, clinical characteristics, triggers, suicidality, and personal burden. Headache 2012;52:99–113.
  7. Ekbom, et al. Age at onset and sex ratio in cluster headache: observations over three decades. Cephalalgia 2002;22:94–100.
  8. May, et al. EFNS Task Force. EFNS guidelines on the treatment of cluster headache and other trigeminal-autonomic cephalalgias. European Journal of Neurology. 2006 Oct; 13(10), p. 1066
Return to Blog