Migraine: when should a headache really worry you?

Migraine affects about 15% of adults, with twice as many women (20%) as men (10%), according to Inserm, the French national institute for health and medical research. In the vast majority of cases, a headache, even a violent one, remains benign. A few specific signs, however, call for medical attention the same day. Here they are: pain that peaks in less than a minute, fever with a stiff neck, a neurological problem that persists, or a new headache after age 50. Here is how to tell the difference, backed by the studies.

Migraine: definition and how it differs from other headaches

Migraine is defined by repeated attacks, not by the intensity of a single episode. The international classification of headache disorders (ICHD-3, International Headache Society, 2018) requires at least 5 attacks lasting 4 to 72 hours. Each one must combine at least two of the following features: pain on one side, throbbing quality, moderate or severe intensity, worsening with routine physical activity. On top of that comes at least one associated sign: nausea or vomiting, or sensitivity to light and noise.

Doctors distinguish primary headaches, which are the disease itself, from secondary headaches. The latter reveal another cause: infection, bleeding, tumor, inflammation of an artery, medication. Migraine and tension-type headache are the two most common primary headaches. Tension-type headache feels like a tight band or a vise on both sides, without nausea, and does not get worse when you climb stairs.

About 20 to 30% of people with migraine experience an aura, according to Inserm. This temporary neurological disturbance, visual in 90% of cases (bright spots, a zigzag line, a blind spot in the visual field), builds up gradually over several minutes. According to the ICHD-3, each symptom lasts between 5 and 60 minutes, then disappears completely. This slow progression and full reversibility set a migraine aura apart from a stroke, which strikes all at once.

Mechanism: what happens in the brain during a migraine attack

A migraine attack stems from a breakdown in communication between neurons and blood vessels, not from a simple “vascular headache.” The research summarized by Inserm describes a cascade in several stages. Scientists link it to the trigeminovascular system:

• a prodromal phase, sometimes 24 hours before the pain, with fatigue, yawning, sugar cravings or neck stiffness, linked to activity in the hypothalamus;
• in patients with aura, a wave of cortical depolarization that spreads slowly across the surface of the brain, which explains the gradual march of visual symptoms;
• activation of the trigeminal nerve, which releases inflammatory neuropeptides, including CGRP (calcitonin gene-related peptide), around the blood vessels of the meninges;
• sensitization of the pain pathways, which makes the scalp tender to the touch and amplifies sensitivity to light;
• a recovery phase, or postdrome, with exhaustion and difficulty concentrating for up to a day after the migraine.

CGRP has become the target of recent preventive treatments for migraine. Its role illustrates a mechanism that aging research calls altered intercellular communication: a poorly regulated chemical signal between nerve, immune and vascular cells keeps local inflammation going. The migraine triggers patients report most often are too little or too much sleep, stress and the letdown after it, skipping a meal, hormonal changes and alcohol. None of these triggers is universal.

What the science says about migraine and serious headaches

Migraine carries a far heavier burden than its frequency suggests. The Global Burden of Disease 2016 study (GBD 2016 Headache Collaborators, Lancet Neurology, 2018) puts the number of people affected at 1.04 billion and the years lived with disability at 45.1 million. Tension-type headache, almost twice as common, causes only 7.2 million. In women aged 15 to 49, migraine alone accounts for 20.3 million years of disability.

More than half of people with migraine describe disabling attacks. The American AMPP survey of 162,576 people (Lipton et al., Neurology, 2007) found a one-year prevalence of 11.7% (17.1% in women, 5.6% in men). Among those affected, 31.3% had at least 3 attacks a month and 53.7% reported severe impairment or needing bed rest. One in four would qualify for preventive treatment, but only 13% were taking one.

In the same survey, prevalence peaked in midlife and became markedly lower after age 60. That is why a headache appearing for the first time in an older person should prompt a search for another cause. The SNNOOP10 list of warning signs (Do et al., Neurology, 2019) lists 15 red and orange flags. They include fever, a history of cancer, a neurological deficit, and a sudden onset or onset after 65. Added to these are a change in pattern, positional pain, pain triggered by coughing or exertion, papilledema, pregnancy, a painful red eye, trauma, immunosuppression and painkiller overuse.

Thunderclap headache is the best-studied warning signal. In a Canadian cohort of 3,132 adults who came to the emergency department with a headache peaking in less than an hour (Perry et al., BMJ, 2011), 7.7% had a subarachnoid hemorrhage. A CT scan performed within 6 hours detected all 121 cases in this subgroup. Hence the value of calling quickly: past that window, the sensitivity of the CT scan declines and a lumbar puncture is often needed.

The Ottawa rule, validated in 2,131 patients (Perry et al., JAMA, 2013), helps emergency physicians sort out these sudden headaches. It looks at age 40 or older, neck pain or stiffness, loss of consciousness witnessed by someone, onset during exertion, pain that is instantly at its peak and limited neck flexion. With these six criteria, its sensitivity reaches 100% for subarachnoid hemorrhage.

Migraine with aura comes with a modestly increased vascular risk. A meta-analysis of 9 studies (Schürks et al., BMJ, 2009) links migraine with aura to a 2.16-fold risk of ischemic stroke, while migraine without aura shows no significant association (1.23). The risk climbs with smoking and the combined estrogen-progestin pill. The Nurses’ Health Study II followed 115,541 women for 22 years (Kurth et al., BMJ, 2016). Migraine was associated with a 50% higher risk of a major cardiovascular event (HR 1.50). These are observational associations: they do not prove that the attack itself causes the event.

In practice: the migraine and headache signs that should alert you

A headache should worry you when it is new, sudden or different from your usual migraine attacks. A known migraine, which has returned with the same features for years, does not need a CT scan or an MRI. The table below compares the three main situations a doctor encounters when faced with a headache.

Most red flags call for a prompt medical evaluation, but not all with the same urgency. This second table, built from the SNNOOP10 list and the Ottawa rule, shows the right response for each signal.

For people living with frequent attacks, several lifestyle levers are documented. Regular sleep is among the most solid, as detailed in our article on sleep and aging. Stress, a trigger cited by most patients, also has measurable long-term effects, described in our feature on chronic stress. These signaling mechanisms are presented in our pillar page on altered intercellular communication.

Tips for living better with migraine and preventing attacks

The first useful step is to keep a headache diary for at least 2 months. It helps your doctor confirm the diagnosis, count your headache days and identify your own triggers. For each episode, write down:

• the date, the time the pain started and how long it lasted;
• its intensity from 0 to 10 and the associated signs (nausea, aura, sensitivity to light);
• the medication taken, the dose and how well it worked 2 hours later;
• the context: a short night, a skipped meal, your period, alcohol, a stressful episode or a relaxed weekend.

Acute treatment works best when taken early, as soon as the pain begins. Beyond 2 or 3 migraine attacks a month, preventive treatment is worth discussing with your doctor. The same applies if attacks make you miss work. In the STRIVE trial of 955 patients (Goadsby et al., NEJM, 2017), erenumab was tested in patients who had an average of 8.3 migraine days a month. This antibody, which blocks the CGRP receptor, cut that number by 3.7 days at the 140 mg dose, compared with 1.8 on placebo.

Some supplements have been tested in controlled trials, with small sample sizes. High-dose oral magnesium (600 mg a day for 12 weeks) reduced attack frequency by 41.6%, compared with 15.8% on placebo, in 81 patients (Peikert et al., Cephalalgia, 1996). The downside: diarrhea in 18.6% of participants. The different forms are compared in our guide magnesium: which form to choose. Riboflavin (vitamin B2, 400 mg a day) doubled the responder rate, 59% versus 15%, in a trial of 55 patients (Schoenen et al., Neurology, 1998). These doses exceed usual intakes and should be decided with a healthcare professional, especially in case of kidney failure.

Endurance exercise is a drug-free preventive option for migraine. In a Swedish trial of 91 patients (Varkey et al., Cephalalgia, 2011), 40 minutes of indoor cycling 3 times a week reduced attacks by 0.93 per month on average. That is as much as relaxation or topiramate. The best-supported prevention habits can be summed up as follows:

• keep stable bedtimes and wake-up times, including on weekends;
• avoid skipping meals and drink regularly throughout the day;
• limit painkillers to fewer than 10 days a month, triptans included;
• practice moderate endurance activity, starting gently;
• quit smoking, especially if you have migraine with aura, and mention the aura before starting any combined estrogen-progestin contraception;
• have your blood pressure checked, because untreated hypertension adds to the vascular risk.

Painkiller overuse remains the most common trap. Medication overuse headache affects 1 to 2% of the general population (Diener et al., Lancet Neurology, 2019) and turns episodic migraine into a near-daily headache. Its treatment begins with a supervised reduction in doses. The frequency of migraine attacks often drops within a few weeks. To receive our science summaries on the brain and healthy aging, subscribe to our health newsletter.

Frequently asked questions about migraine

How can you tell if a headache is serious?

A headache is potentially serious if it peaks in less than a minute, or comes with fever and a stiff neck, weakness on one side of the body, speech problems or confusion. A new headache after age 50, or one that follows a blow to the head, should also be assessed quickly. For sudden or neurological cases, call 911 (US), 999 (UK) or 112 (Europe).

What is the difference between a migraine and a tension-type headache?

Migraine causes attacks lasting 4 to 72 hours, often one-sided and throbbing, worsened by exertion and accompanied by nausea or sensitivity to light. Tension-type headache squeezes both sides of the head like a vise, stays mild to moderate and does not get worse with movement. It is twice as common, but far less disabling, according to the Global Burden of Disease.

Does migraine with aura increase the risk of stroke?

Yes, modestly. A meta-analysis published in the BMJ in 2009 links migraine with aura to a 2.16-fold risk of ischemic stroke, with no significant association for migraine without aura. The absolute risk remains low in a young non-smoker. Smoking and the combined estrogen-progestin pill raise it markedly: always tell your doctor about an aura before starting contraception.

Why can painkillers make headaches worse?

Taken too often, painkillers sustain a sensitization of the pain pathways and cause medication overuse headache. The threshold set by the international classification is 15 days a month for acetaminophen (paracetamol) or anti-inflammatories, and 10 days for triptans or combination drugs. This headache affects 1 to 2% of the population and often improves after a supervised withdrawal.

Can migraine start after age 50?

A first migraine after age 50 is rare, because most patients have their first attack before 40 and frequency declines after 60. A new headache at this age must first lead doctors to rule out a secondary cause, particularly giant cell arteritis, which threatens vision, as well as a tumor or a hematoma. The doctor usually orders a blood test and sometimes imaging.