What Causes Chronic Migraines? 12 Things That Can Trigger These Headaches

Migraines are intense headaches that can cause fatigue, nausea, light flashes, and other physical symptoms. When they are chronic—recurring and existing for extended periods—they can shut down your life as you close yourself up into a quiet, dark, and cool cocoon. That's nobody's idea of a good time. But why do people develop chronic migraines?

Migraines are miserable, and for some people, they happen regularly—more than twice a week, or, as the International Classification of Headache Disorders defines them, 15 headache days a month with at least eight of those having migrainous features.

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What Causes Chronic Migraine?

Unfortunately, it's not entirely clear what causes chronic migraines—or migraines in general. But there are a few theories as to what could be behind them. According to the Mayo Clinic, they include:

  • family history/genetic predisposition
  • imbalances in brain chemicals like serotonin
  • changes to the brainstem and how it interacts with the trigeminal nerve

Other conditions, like vascular malformations or brain injuries, can look identical to migraines, explains Robert Cowan, MD, professor of neurology and chief of the division of headache medicine at Stanford University. But these fall under a different umbrella ("secondary headache") than migraines.

Who's at Risk for Chronic Migraine?

Some people are more likely than others to develop chronic migraines. You cannot change certain risk factors, while others may be modifiable. They include:

Family history. If one or both of your parents has migraines, you have a 50-75% chance of developing them, according to the American Migraine Foundation.

Age. Migraines can start at any age—as young as adolescence—but they're often worst in your 30s before becoming less frequent and severe, says the Mayo Clinic.

Sex. Women get the short end of the stick here—they're three times more likely than men to get migraines, the Mayo Clinic points out.

Certain medical conditions. The American Migraine Foundation lists depression, anxiety, obesity, and snoring among a number of conditions associated with a greater likelihood of having migraine episodes that can lead to chronic migraines.

What Triggers a Chronic Migraine?

While the cause of migraines isn't totally clear, doctors have gained a better understanding of what's happening when migraines start to become chronic. A migraine "is a problem with how you interpret sensory stimuli from your body and from the environment," explains Dr. Cowan. "Your brain starts to adapt. It lowers its pain threshold. It's almost like when you hear a sound in the night, suddenly your senses seem to be heightened."

A variety of lifestyle and environmental factors, known as "triggers," can set off a migraine episode.

"Triggers are very real for some people," says Mason Dyess, DO, a general neurology and headache medicine physician at Ochsner Medical Center in New Orleans. But Dr. Dyess emphasizes that the better you're managing your migraines—by working with a doctor on preventive strategies and pain management when a migraine strikes—the less you have to worry about triggers.

"Traditionally, the better controlled your headaches are, the fewer you have per month, and the faster you can stop them, the less sensitive you are to triggers," he says.

Until your migraines are under control, "if you know something's going to give you a migraine, avoid it, especially until we get a strong preventive and acute regimen in place for you," he says.

Some of the most common triggers include:

Change in Sleep

Particularly "if you don't sleep well," Dr. Cowan says, although sleeping too much can also be a trigger, information from the Mayo Clinic tells us.

Change in Physical Activity

It depends on how active you already are, but say you're not much of a runner and you decide to tackle a half-marathon—that can be a trigger, Dr. Cowan explains. Intense physical exertion (even sexual activity) can incite a migraine, per Mayo Clinic.

Change in Eating Patterns

"Not so much what you eat but when you eat," Dr. Cowan says. "Skipped meals are a big trigger. Overeating can be a big trigger."

Stress

"Anything can be stressful," Dr. Cowan says. Too much screen time, a pet pooping where they're not supposed to, an argument with your spouse. But unfortunately, stress can set off a migraine.

Loud Sounds, Strong Scents, or Bright Light

Dr. Cowan knows this one first hand. "If I walk into the wrong entrance of Nordstrom, through the perfume counters, I'll never make it to the men's section. I'll have a headache that quickly," he says. For other people that might be a particularly loud noise or a bright room.

Medication Overuse

If you're constantly popping pills to relieve migraine pain, you may be setting yourself up for additional headaches. So-called medication overuse headaches, or rebound headaches, are a consequence of frequent use of over-the-counter pain relievers and certain acute migraine medicines, per the Mayo Clinic.

Poor Posture

"When you're tensing the neck muscles, which is what happens with bad posture, you're irritating trigeminal nerves as well, and that's what sets up the tension," Dr. Cowan says.

Caffeine and Alcohol

If you're a regular caffeine drinker and miss your morning cup, that can bring on a migraine, Dr. Cowan says. Alcohol is a trigger for many migraineurs, too.

Certain Foods and Food Additives

Food triggers are entirely dependent on the person, says the American Migraine Association. Chocolate, aged cheeses, salty foods, and food additives like aspartame and MSG are among the ones migraineurs mention most often.

Dehydration

Some people with migraine pain find that becoming parched can lead to another migraine, notes the American Migraine Association.

Hormone Changes

Some women get headaches right before their period starts, Dr. Cowan says, and that's usually due to a drop in estrogen. But researchers are learning more about other hormone changes that might impact migraines.

Weather Changes

Many migraineurs say their headaches come on when the humidity changes, during storms, or in extremely dry conditions. For most of these people, what's actually bothering them is "a change in barometric pressure," Dr. Cowan says. "Your eyeballs are actually your barometric monitor, that's where the brain perceives changes in barometric pressure, and also in the tympanic membrane in the ear."

All of these triggers have something in common. "People with migraines like things steady and predictable," he says. "When you vary from those patterns, your brain thinks there's something wrong."

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