by Patrick Sullivan

Headaches are a fact of life. Collectively, they're the most common neurological disorder, and almost everyone has one at some point in their lives. Most headaches—even the really nasty ones like migraines — won’t have any long-lasting consequences. “They’re serious in that they’re severe and debilitating, but they aren’t lifethreatening,” says Neurologist Robert Coni, DO.

Certain headaches, however, can sometimes make neurologists worry. And symptoms that appear with a headache or a changing headache pattern could be a sign of a serious condition. Learn which headaches are safe, and which might mean an emergency.

Primary or Secondary?

There are many different types of headaches, but healthcare providers usually group them into one of two categories: primary or secondary. “With a primary headache, the headache is actually the disease,” says Dr. Coni. These include cluster headaches, tension headaches and migraines. They can make you miserable, but they’re not deadly.

It’s the secondary headaches—where the headache is a symptom of another disease—that you should worry about, because they could signal a real problem.

What to Look For:

Even if you have a primary headache, you can still develop a hazardous secondary headache. Neurologists look to other symptoms to help them determine what type of headache you have—and if it might be dangerous. “We look for systemic signs like a fever, weight loss or generalized weakness,” Coni says. “Those are unusual for primary headaches.” He’ll also look for neurological symptoms of a stroke, such as weakness or a loss of sensation in one half of the body, facial paralysis or one arm drifting down.

A changing headache pattern is also cause for concern. “If someone goes from having intermittent headaches twice a month to daily, or they get headaches in unusual circumstances, that’s a sign of danger,” says Coni. “If it’s an older person with a new headache, that’s worrisome. Migraines usually present before someone is in their 30s,” he adds. If you notice any of these signs or patterns, see a healthcare provider immediately.


If your headache comes with a stiff neck, a fever and possibly a rash, it could be a sign of an emergency. They're all symptoms of meningitis, a potentially deadly inflammation of the protective lining around the brain and spinal cord. Nausea, vomiting, confusion and sensitivity to light are also symptoms.

Most meningitis cases are caused by viruses, though bacteria and even fungi can also trigger it. “It often looks like an upper respiratory infection with a headache, and it can be lethal if it’s not treated early,” Coni says. Meningitis is contagious and outbreaks often happen when people live close to each other, like in a dorm or elder care facility.


Whereas meningitis is inflammation of the brain’s protective membrane, encephalitis is inflammation of the brain itself, most often caused by a virus. Though children are at greater risk for the condition, “Adults can get it too,” says Coni.

Like meningitis, mild cases of encephalitis can mimic the flu, with a minor headache, sore throat, cough and fatigue. Severe encephalitis can cause a more painful headache, as well as sudden fever, drowsiness, vomiting, confusion, hallucinations, muscle weakness, sudden and severe dementia, memory loss, partial paralysis and seizures.


An aneurysm is the ballooning of an artery due to a weakness in the artery wall. It can occur in any artery, but is most often found in the abdominal aorta or brain. You can have an aneurysm for years without knowing it, since it typically doesn’t have any symptoms—that is, until it bursts (also called a rupture). At that point, it can cause a bleeding around the brain—called a subarachnoid hemorrhage—or in the brain, known as a hemorrhagic stroke. A sudden, severe headache—one that you might call the worst headache of your life—is one sign of a ruptured brain aneurysm. Nausea, vomiting and drowsiness are other symptoms of a brain bleed, and weakness, facial drooping and difficulty speaking are red flags of a stroke. A ruptured brain aneurysm is fatal between 30 and 40 percent of the time.

Ischemic Stroke

As far as strokes go, hemorrhagic strokes are rare; they make up about 15 percent of all strokes. Much more common are ischemic strokes, which are caused by a blockage cutting off blood supply to the brain. “These can be associated with headaches,” says Coni, “and there’s usually neurological dysfunction that occurs at the same time as a headache.”

If you’re worried that you or a loved one may have had a stroke, you need to act F.A.S.T. If you notice facial drooping, arm weakness and speech trouble, it’s time to get to the emergency room.

Concussion or TBI

Headaches are one of the most common complications of a traumatic brain injury (TBI) or concussion, which is a mild form of TBI. About 30 percent of people who have had a TBI get headaches for a long time after their injury. Concussion symptoms can be easy to miss and you might not make the connection between the symptoms and the accident.

If you’ve had a head injury recently, and you have a stubborn headache that gets worse, seek medical attention. Other danger signs can include:

  • Weakness
  • Numbness
  • Decreased coordination
  • Nausea and vomiting
  • Slurred speech
  • Seizures
  • Unresponsiveness
  • One pupil bigger than the other
  • Confusion