Large Study of Painful Cluster Headaches Has Revealing Findings Interview with:
Mark J. Burish, MD, PhD.
Assistant Professor
Vivian L. Smith Department of Neurosurgery
Director, Will Erwin Headache Research Center
McGovern Medical School at UTHealth Houston

Dr. Mark Burish – Neurosurgery
Photo by Dwight C. Andrews/The University of Texas Medical School at Houston Office of Communications  What is the background for this study?  Would you describe cluster headaches?

Response: Cluster headache is a disease associated with excruciating attacks of one-sided pain around the eye – patients regularly say it is more painful than childbirth, kidney stones, or gunshot wounds.  The attacks last between 15 minutes and 3 hours and can occur up to 8 times per day.  During an attack, patients will often have changes around the eye (such as a watery or bloodshot or droopy eye) changes in the nose (like congestion and a runny nose), and a restless feeling like they can’t sit still.  It is called “cluster” headache because, for most patient, the headaches occur every day for several weeks then go away for the rest of the year, only to come back the following year.  This is called “episodic” cluster headache, though there is another version called “chronic” cluster headache in which the headaches occur at least 9 months a year.

Cluster headache is found in about 1 in 1000 patients.  Because it is uncommon, there have not been a lot of large international studies investigating basic questions like the age that these headaches start and the differences from patient to patient.  There is a great need to understand more about this disorder at every level.  So two researchers from the University of West Georgia (Larry Schor and Stuart Pearson) performed a large epidemiology study on cluster headache because very few have been done.  They created an online questionnaire and advertised it internationally.  They ended up obtaining the largest study in terms of participants and the most international study ever performed (at least to our knowledge).  They then asked for help analyzing it from several physicians (including myself) and statisticians.  I felt very fortunate that they reached out to me and I really enjoyed working on this project because I think it gives us a lot of insights into cluster headache.  What are the main findings?

Response: Our study found that cluster headache affects not only men but also women, children, and adolescents.  The most surprising finding was the number of people whose headaches started before age 18 – over a quarter (actually 28%) of the 1604 people that we analyzed.  Those patients, unfortunately, are typically not diagnosed until adulthood (only 15% of our respondents with pediatric onset were diagnosed before age 18).  We also found that first-line medications for cluster headache (oxygen and calcium channel blockers) are less effective in chronic cluster headache, which supports recent clinical trials of new drugs and devices that also found chronic cluster headache to be less responsive to treatment. What should readers take away from your report?

Response: Cluster headache is not just a disease of adult men as is traditionally thought – children and adolescents of both genders get cluster headache, and women in many ways have stronger cluster headache features (more pain intensity, higher depression scores, and more nausea, vomiting, and restlessness).  Pediatrics is a real area of need, as most patients do not get diagnosed until they become adults.  And cluster headache is treated differently than other headaches, undiagnosed and misdiagnosed patients likely do not receive the correct treatments until they are correctly diagnosed.  Chronic cluster headache is another real area of need, as the medications do not work as well as they do for episodic cluster headache. What recommendations do you have for future research as a result of this work?

Response: Because this disease happens in young patients, and because many (about 11%) had a family history of cluster headache, genetics will be an interesting area of future research.  Two large genetics studies were published in Europe this year and are an exciting direction for the field.  Understanding why children and adolescents don’t get diagnosed until adulthood, and understanding why chronic cluster headache patients don’t respond to treatments as well as episodic cluster headache patients, are also important to study.

Disclosures:  The study was funded by Autonomic Technologies Inc (a device company that studies cluster headache) and Clusterbusters (a patient support organization).


Schor, LI, Pearson, SM, Shapiro, RE, Zhang, W, Miao, H, Burish, MJ. Cluster headache epidemiology including pediatric onset, sex, and ICHD criteria: Results from the International Cluster Headache Questionnaire. Headache. 2021; 00: 1– 10. doi:10.1111/head.14237

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Last Updated on December 10, 2021 by