An acute migraine is a single migraine attack, the distinct episode of head pain and associated symptoms that lasts anywhere from 4 to 72 hours if untreated. The term “acute” distinguishes the individual attack from chronic migraine, which is defined as 15 or more headache days per month for at least three months. Most people with migraine have the episodic form, meaning fewer than 15 headache days per month, and each of those episodes is an acute attack.
How an Acute Migraine Is Diagnosed
A migraine isn’t just a bad headache. To qualify, the pain needs at least two of these four features: it’s on one side of the head, it pulses or throbs, it’s moderate to severe in intensity, or it gets worse with routine physical activity like walking or climbing stairs. On top of the pain, you also need at least one of the following: nausea or vomiting, or sensitivity to both light and sound. These criteria come from the International Classification of Headache Disorders, which doctors use worldwide.
There’s also a frequency threshold. A diagnosis typically requires at least five attacks meeting those criteria, and each attack must last between 4 and 72 hours when untreated. That time range is important because a headache that resolves in under four hours or lasts longer than three days may point to a different type of headache disorder entirely.
The Four Phases of an Attack
A migraine attack isn’t just the headache. It can unfold in up to four distinct phases, though not everyone experiences all of them.
The prodrome comes first, sometimes hours or even days before the pain starts. This is when you might notice subtle warning signs: food cravings, mood changes, neck stiffness, frequent yawning, or difficulty concentrating. Many people learn to recognize their prodrome over time, which can help with early treatment.
The aura phase affects roughly a quarter of people with migraine. It usually builds over at least five minutes and lasts up to 60 minutes. Visual disturbances are the most common type: flickering lights, zigzag lines, or blind spots. Some people experience tingling in their face or hands, or temporary difficulty speaking. Aura almost always resolves completely before or during the headache phase.
The headache phase is the main event, lasting from several hours to up to three days. This is when the throbbing pain, nausea, and sensitivity to light and sound hit hardest. Many people find they need to lie still in a dark, quiet room because any movement or stimulation makes things worse.
The postdrome, sometimes called a “migraine hangover,” follows the pain. It varies in length and often leaves people feeling drained, foggy, or mildly confused. Some describe it as feeling washed out for the rest of the day.
What Happens in the Brain During an Attack
Migraine isn’t caused by blood vessels expanding in the skull, as scientists once believed. The current understanding centers on the trigeminal nerve, a major pain-signaling pathway that connects the brain’s outer lining (the meninges) to the brainstem. During an attack, nerve fibers in this system release a signaling molecule called CGRP from their endings along the blood vessels of the meninges.
CGRP itself doesn’t directly cause pain. Instead, it kicks off a cascade: it triggers the release of nitric oxide, which dilates blood vessels and, critically, sensitizes nearby nerve endings. Those sensitized nerves release even more CGRP, and the two substances amplify each other in a feedback loop. This process, called peripheral sensitization, is why the throbbing pain can intensify so quickly. Over time during an attack, this sensitization can spread to second-order neurons deeper in the brainstem, a shift called central sensitization. Once central sensitization sets in, even normally painless stimuli like light touch on the scalp or combing your hair can become painful. This is also why treating early matters: it’s easier to interrupt the cascade before central sensitization takes hold.
Common Triggers
Migraine attacks are often set off by identifiable triggers, though they vary widely from person to person. The most commonly reported include psychological stress, weather changes, disrupted sleep patterns, and certain foods or drinks.
Among dietary triggers, alcohol stands out. Red wine is the most frequently cited alcoholic trigger, reported by about 78 to 91% of migraine patients who identify alcohol as a problem. Interestingly, fewer than 9% of those people get an attack every single time they drink red wine, suggesting that alcohol often works in combination with other factors rather than acting alone. Other food-related triggers include caffeine (both consuming it and withdrawing from it), aged cheeses containing tyramine, processed meats with nitrates, MSG, and chocolate. In one prospective study, about 10% of migraine patients identified cheese as a trigger, and nearly 5% recorded attacks on days they consumed nitrates.
Hormonal shifts are a major trigger for women, particularly the drop in estrogen around menstruation. Skipping meals, dehydration, bright or flickering lights, strong smells, and intense physical exertion can also provoke attacks.
How Acute Migraine Is Treated
Treatment for an individual migraine attack depends on severity, and timing is everything. For mild to moderate attacks, over-the-counter pain relievers like ibuprofen, aspirin, or a combination of aspirin, acetaminophen, and caffeine are considered first-line options. These work best when taken as early as possible once the headache begins.
For moderate to severe attacks, or when over-the-counter options don’t provide relief, triptans are the standard treatment. Seven different triptans are available, and they work by targeting serotonin receptors involved in the migraine cascade. In clinical trials, oral sumatriptan at the 100 mg dose left 50% of patients completely pain-free at two hours, compared to 16% with placebo. That number climbed when people took it while the pain was still mild, reinforcing the advantage of early treatment. One important caveat: triptans taken during the aura phase, before any headache has started, are not effective.
A newer class of medications called gepants works by blocking the CGRP receptors directly, targeting the same signaling molecule that drives the attack. These offer an alternative for people who can’t tolerate triptans or have cardiovascular conditions that make triptans unsafe.
The Risk of Medication Overuse
Using acute migraine treatments too frequently can paradoxically cause more headaches, a condition called medication overuse headache. The thresholds vary by drug type. Triptans, opioids, and combination analgesics become risky at 10 or more days per month for three or more months. NSAIDs and acetaminophen have a slightly higher threshold of 15 days per month over the same period.
This is one of the key reasons doctors recommend preventive treatment for people who have frequent attacks. If you’re reaching for acute medication more than two or three days a week on a regular basis, the medication itself may be contributing to a cycle of increasingly frequent headaches.
Acute vs. Chronic Migraine
The dividing line is 15 headache days per month. Episodic migraine means 0 to 14 headache days per month, and each of those episodes is an acute attack. Chronic migraine means 15 or more headache days per month for at least three months, with at least 8 of those days meeting migraine criteria or responding to migraine-specific treatment.
Chronic migraine isn’t a separate disease. It’s what can happen when episodic migraine progresses over time, often driven by risk factors like medication overuse, obesity, sleep disorders, stress, or inadequate treatment of acute attacks. About 3% of people with episodic migraine transition to chronic migraine each year, which is why effective management of acute attacks plays a role in prevention.
Red Flags That Warrant Urgent Attention
Most headaches, even severe ones, are not dangerous. But certain features signal that a headache could be caused by something more serious than migraine. A sudden-onset headache that reaches maximum intensity within seconds (sometimes called a “thunderclap headache”) is the most critical, as it can indicate bleeding in the brain. Other warning signs include a headache accompanied by fever, a new headache in someone over 50 who has never had migraines, headaches that are progressively worsening over weeks, headaches triggered by coughing or exertion, headaches with neurological symptoms that don’t fit a typical aura pattern (such as seizures, weakness, or confusion), and any headache following head trauma.
Migraine is the third highest cause of disability worldwide, behind stroke and a type of brain injury affecting newborns. Globally, headache disorders affect roughly 40% of the population. Despite this enormous burden, many people with migraine remain undiagnosed or undertreated, often because they assume their attacks are “just headaches” that don’t merit medical evaluation.