The chronic migraine criteria that govern on-label neurotoxin treatment are narrower than most injectors assume, and the gap between "this patient gets a lot of headaches" and "this patient meets the indication" is where practices get into trouble. Patients will tell you they have migraines. Some of them will be right. Your job before you open a vial is to establish that this person sits inside a defined clinical category, that somebody qualified put them there, and that you can prove it from the chart rather than from memory.
This is gatekeeping, and it is yours. Nobody downstream is going to catch it.
Start with the sentence on the label, and treat every clause as a gate
BOTOX is indicated "for the prophylaxis of headaches in adult patients with chronic migraine (≥15 days per month with headache lasting 4 hours a day or longer)."
Four gates in one sentence.
Prophylaxis. This is a preventive. It does nothing for the attack in front of you and it is not a rescue treatment. If a patient's expectation is that you will abort headaches, you have a consent problem before you have a clinical one.
Adult. A separate trial in adolescents did not establish efficacy versus placebo, and the label says so explicitly. There is no on-label paediatric use here.
≥15 days per month. Not fifteen migraines. Fifteen headache days — a distinction I will come back to, because it cuts both ways.
Lasting 4 hours a day or longer. This is the clause most often dropped in conversation, and it is the one Dr. Croley flags in teaching: this is not "I had a headache for a couple of hours." The trials enrolled patients with headache days of four hours or more. A patient with twenty brief headaches a month has not met the criterion.
Then read the Limitations of Use, which is the most useful sentence on the page: safety and effectiveness "have not been established for the prophylaxis of episodic migraine (14 headache days or fewer per month) in seven placebo-controlled studies."
Seven. That is not silence, it is a repeated negative result. When a patient with eight bad headaches a month asks for this, you are not declining because of a technicality. You are declining because the evidence base at that headache frequency says it does not beat placebo.
Headache days and migraine days are different counts
The label counts headache days. The diagnostic classification counts both. If you only ever ask "how many migraines a month," you will mis-sort patients in both directions.
The International Classification of Headache Disorders, 3rd edition, defines 1.3 Chronic migraine as:
- A. Headache (migraine-like or tension-type-like) on ≥15 days/month for >3 months, and fulfilling criteria B and C
- B. Occurring in a patient who has had at least five attacks fulfilling criteria B–D for 1.1 Migraine without aura and/or criteria B and C for 1.2 Migraine with aura
- C. On ≥8 days/month for >3 months, fulfilling any of the following: criteria C and D for 1.1 Migraine without aura; criteria B and C for 1.2 Migraine with aura; or believed by the patient to be migraine at onset and relieved by a triptan or ergot derivative
- D. Not better accounted for by another ICHD-3 diagnosis
(International Classification of Headache Disorders, 3rd edition, ichd-3.org.)
Three things follow that matter at the chairside.
Criterion A counts tension-type-like days. ICHD-3 is explicit in its notes that in this population the individual episodes cannot be reliably separated — the character of the headache "may change not only from day to day but even within the same day" — so both migraine-like and tension-type-like days count toward the fifteen. A patient who says "only eight of them are proper migraines, the rest are just headaches" may still qualify. Do not let them disqualify themselves.
Criterion B is a history requirement, not a current one. There must be an established prior pattern of at least five attacks meeting full migraine criteria. This is the clause that separates chronic migraine from a chronic headache disorder that has never been migraine.
Criterion C is the floor that keeps this from being chronic tension-type headache. At least eight days a month must carry migraine features, or be triptan/ergot-responsive attacks the patient identified as migraine at onset.
And note that because tension-type-like headache sits inside the chronic migraine criteria, this diagnosis excludes a concurrent diagnosis of tension-type headache. If a referral letter says "chronic tension-type headache," that is not a chronic migraine diagnosis with a synonym; it is a different diagnosis, and it is not the indication.
">3 months" is doing real work
Both the fifteen-day and the eight-day criteria require more than three months. Not one bad quarter. Not the three weeks since a car accident.
This period requirement is the reason a recent-onset picture should slow you down rather than speed you up. A headache pattern that started inside three months is, by definition, not yet chronic migraine, and a recently-changed pattern is a recognised red flag for a secondary cause. The companion resource on secondary-headache red flags covers what to do with that patient. For the purposes of this article: they do not meet criteria, so the question of whether to treat them on-label does not arise.
There is also a differential the classification calls out directly. New daily persistent headache can look like chronic migraine. ICHD-3's rule is that where the headache was unambiguously daily and unremitting from less than 24 hours after its first onset, it should be coded as new daily persistent headache instead. So the question "was there a day this started, and was it immediately constant?" belongs in your intake.
The diary is the criterion. The intake form is not.
ICHD-3 states that characterising frequently recurring headache "generally requires a headache diary to record information on pain and associated symptoms day-by-day for at least one month."
That is not administrative garnish. A patient's recalled headache-day count is one of the least reliable numbers in medicine, and it is the number the entire indication turns on. Retrospective estimates cluster at round figures and drift upward when someone is hoping to qualify for a treatment.
If you are going to offer this, require a month of prospective diary data before the first injection. You need it three times over: to establish eligibility, to create the baseline you will measure response against, and to document acute medication intake so you can identify medication overuse. Practices that skip it end up with no defensible way to say whether the treatment worked, which is a problem I address in the companion piece on therapeutic endpoints.
Medication overuse: code both, and expect a proportion to reclassify
The most common cause of symptoms that look like chronic migraine is medication overuse. ICHD-3 is unusually blunt about the consequences: around 50% of patients who appear to have chronic migraine "revert to an episodic migraine type after drug withdrawal," and are in a sense wrongly diagnosed. Its rule is that a patient meeting criteria for both chronic migraine and medication-overuse headache should be coded for both, and re-diagnosed after withdrawal.
Translate that into clinic. One in two apparent chronic migraine patients with acute medication overuse is not going to be a chronic migraine patient three months after they stop overusing. If you inject that patient and they improve, neither of you will ever know which intervention did it.
The European Headache Federation consensus states that in patients with chronic migraine and medication overuse "it is preferable to detoxify first with later initiation of onabotulinumtoxinA," while allowing that where that is not feasible, treatment can be started from the outset (Bendtsen L, Sacco S, Ashina M, et al. Guideline on the use of onabotulinumtoxinA in chronic migraine: a consensus statement from the European Headache Federation. J Headache Pain. 2018;19(1):91). That is a reasonable framework for a practice: ask about acute medication intake, count it from the diary, and if it is high, that conversation happens before the injection appointment, not after.
"Failed other therapies" — what that clause actually means
Both the coverage conversation and good clinical practice require a history of inadequate response to other preventive treatment. Dr. Croley teaches it as part of the eligibility picture: more than fifteen headache days a month that have not responded to other therapies, over a defined period.
The EHF consensus puts a number on it: patients "should have failed at least two to three other migraine prophylactics unless contraindicated by comorbid disorders."
What you need in the chart is not a vague "tried a few things." It is: which agents, at what dose, for how long, and why they were stopped — lack of efficacy, intolerance, or contraindication. A patient who took a preventive for ten days and disliked it has not failed it. A patient who cannot take a beta blocker because of their asthma has a contraindication, which is a different and equally valid entry.
Review the prior prevention strategy properly. What medications have they been on, what treatments have they tried, what worked, what failed. That history tells you as much about the likely response as the headache count does.
Who made the diagnosis, and can you see it
The cleanest patient in this category arrives with a diagnosis of chronic migraine made by a neurologist or a primary care physician who has completed the appropriate workup. That patient you can take forward.
The patient who has diagnosed themselves, or who was told years ago that they "get migraines," is not that patient. Neither is the patient whose diagnosis exists only in a phone conversation you cannot obtain a record of. Request the records. If they do not exist, the referral goes outward before anything goes in.
I want to be precise about why. This is not defensive medicine theatre. Aesthetic practices are structurally biased toward yes — we are configured to convert consultations — and an undiagnosed secondary headache walking into that environment is how a serious diagnosis gets delayed by a year of quarterly injections.
The documentation you should hold before the first injection
- A chronic migraine diagnosis from a qualified diagnosing clinician, in writing, with the workup that supports it
- At least 28 days of prospective headache diary: headache days, duration, severity, and acute medication use
- The headache-day count and the migraine-feature-day count, recorded separately
- Duration of the pattern, with an explicit note on onset and whether it was abrupt and immediately continuous
- A prior preventive list with agent, dose, duration and reason for discontinuation
- An acute medication overuse assessment
- A documented baseline functional measure you intend to re-measure
- Consent that names the treatment as preventive, states the expected magnitude of benefit, and — if you are not billing insurance — states the off-label status explicitly
Empire's guidance on what to include in Botox consent forms is the starting point for that last item, with the therapeutic-specific additions covered in the cash-pay piece in this cluster.
The patient who does not meet criteria
Some will not, and you should have a plan that is not simply "no."
A patient with fewer than fifteen headache days a month is outside the indication and outside the evidence. A patient with brief headaches is outside the four-hour criterion. A patient with a three-week-old pattern needs a diagnosis, not a treatment. In each case the right move is a referral and, if appropriate, an invitation to come back with a diary and a diagnosis.
There is a separate route — cash-pay, explicitly off-label, tailored rather than protocol-driven — and it is a legitimate way to practise. But it is not a way to treat a patient who fails the criteria and pretend they passed. The off-label path means telling the patient plainly that this use has not been approved for their situation and documenting that you did. That is covered in its own piece.
This guidance reflects Dr. Chris Croley's clinical practice as taught in Empire Medical Training's hands-on curriculum, together with the FDA-approved labelling, ICHD-3 and the consensus guidance cited. This article is educational and is not a substitute for training or for a diagnosing clinician's judgement.
Related guides in this cluster
Part of Therapeutic Neurotoxin: Chronic Migraine.
Clinical GuideConfirm the Diagnosis First: Secondary-Headache Red Flags Before You InjectSecondary headache red flags decide whether a migraine patient gets injected or referred. The SNNOOP10 framework, the numbers behind it
Clinical GuideThe PREEMPT Protocol: Why Fixed-Site, Fixed-Dose Was the Trial Design, and What It Means in PracticeThe PREEMPT protocol is fixed-site, fixed-dose for a reason. What the trial design was, why the label is rigid, and where tailoring is
Clinical GuideMigraine Treatment Outcome Measures vs Aesthetic Endpoints: Two Assessment FrameworksMigraine treatment outcome measures are disease burden, not movement. The four domains to record, the responder thresholds to pick, and
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Explore Botox Training & Certification →Disclaimer
This article reflects the clinical opinions and experience of Dr. Chris Croley, Chief Medical Officer, Empire Medical Training, an independent faculty member contributing to Empire Medical Training's curriculum. The views expressed are the author's own and do not necessarily represent those of Empire Medical Training.
It is professional education, not medical advice, and is no substitute for hands-on training or independent clinical judgment. Licensed clinicians remain responsible for their own patient selection, technique and outcomes, for verifying current product labelling, and for practising within their scope and applicable law. Empire Medical Training accepts no liability for reliance on this content.