Is a hemiplegic migraine the same as a stroke?

No. A hemiplegic migraine causes temporary, fully reversible weakness driven by an electrical event in the brain, while a stroke involves lasting damage from interrupted blood flow. The symptoms can look identical, though, so the first time you have these symptoms you should call 911 and let a doctor rule out a stroke.

Is hemiplegic migraine dangerous?

Most attacks resolve within a day without permanent harm. The main danger is that its symptoms mimic a stroke, so any first-time or unusual episode needs urgent medical evaluation. A neurologist can confirm the diagnosis and create a plan to reduce future attacks.

Can hemiplegic migraine be inherited?

Yes. The familial form is passed down in an autosomal dominant pattern, meaning each child of an affected parent has about a 50% chance of inheriting the gene mutation. The sporadic form has the same symptoms but no family history. Mutations in the CACNA1A, ATP1A2, SCN1A, and PRRT2 genes have been linked to the condition.

Why can't I take triptans for hemiplegic migraine?

The FDA contraindicates triptans for hemiplegic migraine. The historical concern was that triptans narrow blood vessels. If you also get typical migraines without weakness, your doctor may still allow triptans for those specific attacks, but this should only be done under medical supervision.

How long does a hemiplegic migraine attack last?

Aura symptoms usually last from about an hour to a day and resolve within 24 hours. Sometimes they persist for several days, and in rare cases weakness can last up to four weeks. Attacks that last longer than usual should be checked by a doctor.

Learning›Science of Skin

Hemiplegic Migraine: Symptoms, Causes, and When It's an Emergency

June 5, 2026

One side of your body suddenly goes weak, your vision blurs, and the words won't come out right. It feels like a stroke, and that fear is completely understandable. For some people, these frightening symptoms are actually a rare form of migraine called hemiplegic migraine.

Hemiplegic migraine is real, it is treatable, and most attacks pass within a day. But because its symptoms overlap so closely with a stroke, it is also one of the few headache conditions where you should not try to figure it out on your own the first time it happens. Here is what it is, why it happens, and when to get help fast.

What is a hemiplegic migraine?

A hemiplegic migraine is a rare type of migraine with aura that causes temporary weakness or paralysis on one side of the body (the word "hemiplegic" means one-sided weakness). The weakness shows up during the aura phase, the warning stage that comes before or alongside the headache, and it is the feature that sets this migraine apart from more common types.

It is genuinely uncommon. A large population study in Denmark found that hemiplegic migraine affects roughly 1 in 10,000 people, or about 0.01% of the population. That figure splits into two forms with identical symptoms: a sporadic form (no family history) and a familial form that runs in families.

Sporadic hemiplegic migraine: occurs in someone with no affected relatives (~0.002% prevalence)
Familial hemiplegic migraine (FHM): at least one close relative is also affected (~0.003% prevalence)
Both forms look and feel the same; family history is what tells them apart

What are the symptoms?

The hallmark is one-sided motor weakness, but most people experience several aura symptoms together. These can be alarming because they closely resemble a stroke. The symptoms typically build up gradually over minutes rather than appearing all at once.

Common symptoms during a hemiplegic migraine attack include:

Weakness or temporary paralysis on one side of the body or face
Vision changes such as blurring, blind spots, or flashing lights
Numbness or a pins-and-needles tingling, often spreading along one side
Difficulty speaking or finding words
Confusion, trouble concentrating, or memory gaps
Fatigue, and in some people dizziness or a spinning sensation
A throbbing headache, which may come before, during, or after the other symptoms

How long does a hemiplegic migraine last?

For most people, the aura symptoms of a hemiplegic migraine last from about an hour to a day and resolve completely within 24 hours. The weakness and other neurological symptoms come and go with the attack rather than leaving lasting damage.

In some cases the symptoms linger for several days. Rarely, the weakness can persist for up to four weeks before fully resolving. Because the timeline can be long and the symptoms severe, prolonged attacks are sometimes mistaken for, or need to be ruled out against, a true stroke.

What causes it, and is it genetic?

Hemiplegic migraine has a unique distinction: it is the only headache syndrome tied to known genetic mutations. The familial form is inherited in an autosomal dominant pattern, which means most affected people have one parent who also carries it, and each child of an affected parent has a 50% chance of inheriting the gene.

Researchers have linked familial hemiplegic migraine to mutations in four genes, which create four subtypes. Three of these genes (CACNA1A, ATP1A2, and SCN1A) make proteins that control how ions move in and out of nerve cells, which is central to normal nerve signaling.

The attacks themselves are driven by something called cortical spreading depression, a slow wave of overactive then suppressed nerve cell activity that travels across the surface of the brain. Importantly, this is an electrical event, not a problem with blood flow. That detail matters for treatment.

FHM1 (CACNA1A): the most common subtype; can involve cerebellar signs like coordination problems
FHM2 (ATP1A2): may involve seizures
FHM3 (SCN1A): another ion-channel gene
FHM4: a familial form with no identified gene yet

How is hemiplegic migraine treated?

Treatment is always directed by a doctor, usually a neurologist, and is tailored to how often and how severely attacks occur. There is no single cure, so the goal is to reduce how often attacks happen and to manage symptoms safely when they do.

One key safety point: the FDA contraindicates triptans (a common class of acute migraine drugs) for hemiplegic migraine. The original concern was that triptans narrow blood vessels, and the historical worry was reduced blood flow during an attack. People who also get typical migraines without weakness may still use triptans for those separate attacks, but only under a doctor's direction.

For prevention, doctors have several evidence-supported options to choose from. Specific choices, doses, and combinations are individual medical decisions, so this list is for general education only.

Calcium channel blockers such as verapamil
Acetazolamide, which has shown promise in some patients
Beta-blockers
Antiseizure medicines
Tricyclic antidepressants or SNRIs
CGRP antagonists (a newer class of migraine-specific drugs)
Botulinum toxin (Botox) injections

When should you see a doctor or call 911?

The first time you ever experience one-sided weakness, slurred speech, facial drooping, or sudden vision loss, treat it as a possible stroke and call 911 immediately. These are also classic stroke warning signs (remember FAST: Face drooping, Arm weakness, Speech difficulty, Time to call emergency services), and a stroke is a true emergency where minutes matter. Do not assume it is a migraine until a doctor has evaluated you.

Even after a hemiplegic migraine has been diagnosed, you should seek emergency care if an attack feels different from your usual ones, if symptoms last longer than normal, or if you have new or worsening confusion, a sudden severe headache, or a high fever. Anyone who suspects they have hemiplegic migraine, or who has a family history of it, should work with a neurologist for an accurate diagnosis and a safe, personalized plan.

Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider before starting any new skincare treatment, especially if you have underlying health conditions, are pregnant, or are taking medications.