Migraine or cluster headache? Take the 2-minute check

If you keep getting severe headaches on one side of your head and you are not sure whether they are migraine attacks, cluster headache, or something else, this check gives you a structured first answer. Cluster headache causes attacks of extreme pain centered on one eye that arrive in daily bouts, often at the same times of day and night; the comparison page describes how that differs from migraine. The check uses the three questions of the Erwin Test for Cluster Headache, a screening tool created and validated by headache researchers.^[1] Answering takes about two minutes, and the result tells you what your answers suggest and what to do next.

How this check works

The Erwin Test for Cluster Headache (ETCH) asks about the three features that best separate cluster headache from other headache conditions: how bad the pain is, how long an attack lasts, and whether your eye or nose reacts on one side only. In the validation study, 224 patients at a headache clinic answered the questions themselves on paper, and their results were compared with the diagnosis of a headache specialist.^[1]

The test found 84% of the patients who had cluster headache (sensitivity), and correctly cleared 89% of the patients who did not (specificity). Two points matter when you read your result:

• A "no" result makes cluster headache less likely, though it cannot tell you what your headaches are. Whatever the diagnosis turns out to be, your pain is real. Keep a headache diary that records when attacks start, how long they last, and what they feel like, and see a doctor, ideally a headache specialist, as soon as you can.
• The study took place in a specialist clinic, where cluster headache is far more common than among people taking the test online. A "yes" result means cluster headache is a realistic possibility and worth ruling out with a neurologist; only a doctor can confirm it.

A few rarer conditions from the same family (paroxysmal hemicrania, hemicrania continua, SUNCT) can also produce a positive result. That is still useful information: they respond to specific treatments, and the next step is the same neurologist visit.

Why cluster headache is missed so often

Cluster headache affects about 1 in 1,000 people, and most doctors see it rarely. In a survey of 789 patients, respondents reported receiving an average of 3.9 incorrect diagnoses and seeing 4.3 physicians before cluster headache was identified.^[2] A 2014 hospital study found that about 77% of cluster headache patients had been misdiagnosed at least once, most often with migraine, sinusitis, or dental problems.^[3] A validated screening test exists to shorten that delay.

The official diagnostic criteria (ICHD-3)

Doctors diagnose cluster headache using the International Classification of Headache Disorders (ICHD-3).^[4] The screening questions above are a shortcut; these are the full criteria a neurologist will check:

Criterion	In plain language
At least 5 attacks matching the points below	The pattern must repeat; a single bad headache is not enough
Severe or very severe one-sided pain around the eye, above the eye, or at the temple, lasting 15 to 180 minutes untreated	The pain stays on one side, centered on or near one eye, and an untreated attack ends within 3 hours
On the side of the pain: a red or watering eye, a blocked or runny nostril, a swollen or drooping eyelid, forehead or facial sweating, or a constricted pupil; and/or a sense of restlessness or agitation	During the attack your eye or nose reacts on the painful side, or you cannot sit still
Attacks occur between once every other day and 8 times per day	When a cluster period is active, attacks come frequently
Not better explained by another diagnosis	A doctor rules out other causes

If this table reads like a description of your attacks, take the check above and bring the printed summary to a doctor's appointment.

About the Erwin Test

The Erwin Test for Cluster Headache was developed by researchers at UTHealth Houston and validated in a study published in Cephalalgia in 2021.^[1]

The three questions in the check above are reproduced verbatim, unchanged from the published instrument. The instrument is © 2020 The University of Texas Health Science Center at Houston, reproduced here under the CC BY-NC-ND 4.0 license on a non-commercial patient resource.

References

1. ↩ Parakramaweera R, Evans RW, Schor LI, Pearson SM, Martinez R, Cammarata JS, Amin AJ, Yoo SH, Zhang W, Yan Y, Burish MJ (2021). A brief diagnostic screen for cluster headache: Creation and initial validation of the Erwin Test for Cluster Headache. Cephalalgia, 41(13), 1298–1309. doi:10.1177/03331024211018138
2. ↩ Klapper JA, Klapper A, Voss T (2000). The misdiagnosis of cluster headache: a nonclinic, population-based, internet survey. Headache, 40(9), 730–735. Link
3. ↩ Voiticovschi-Iosob C, Allena M, De Cillis I, Nappi G, Sjaastad O, Antonaci F (2014). Diagnostic and therapeutic errors in cluster headache: a hospital-based study. Journal of Headache and Pain, 15(1), 56. doi:10.1186/1129-2377-15-56
4. ↩ Headache Classification Committee of the International Headache Society (IHS) (2018). The International Classification of Headache Disorders, 3rd edition. Cephalalgia, 38(1), 1–211. doi:10.1177/0333102417738202