6 headache questions answered


Dr. William Spencer Kingston, neurologist and headache specialist at Sunnybrook, answers some frequently asked questions about a very common and potentially debilitating ailment.

How common are headaches?

Headaches are very common.

Most people will experience some form of headache. Tension-type headaches are the most common, but not a common reason to see the doctor since they’re not severe. Migraines are one of the single most common reasons to see a doctor, making up upwards of 10 per cent of all primary care visits. Between 20 and 25 per cent of women and 10 per cent of men will experience migraine at some point in their life, and about 1 billion people are affected worldwide. It’s been rated as the second-most disabling condition that there is.

What’s actually happening inside when you have a headache?

A lot is happening during a headache and it depends a bit on the type of headache. For migraine, a slurry of chemicals get released which trigger “neurogenic inflammation”, which we think leads to the pain and the host of other symptoms that can accompany it. One of the most important chemicals is calcitonin gene-related peptide (CGRP) which is now a target for treatment.

What are some of the causes of headaches?

The vast majority of headaches that doctors see have no underlying cause, per se, and are regarded as a “primary headache disorder”. That is to say that people are born with a susceptibility to getting headaches and other external or internal factors bring them out, or they manifest at a certain age. There are a handful of secondary causes of headaches, but we don’t usually do any testing for headache unless there is an element of a patient’s clinical history or neurological examination that makes us concerned for a secondary cause.

People talk about headache ‘triggers’ – is that evidence-based? Do some things really cause headaches?

Some people may have triggers, some may not. Most people will have some kind of a trigger, but it doesn’t mean it’s reliable. For example, during a premonitory phase of migraine (the hours or days before the pain begins) people may be susceptible to a trigger when they ordinarily wouldn’t be. Common modifiable triggers include poor sleep, stress or stress let-down (the period of relief after a stressful peak) and occasionally certain food. Management of mood and anxiety are very important for management of headache for this reason. Weather changes can be provocative for some people, but we can’t really modify that. I tell people to be on the lookout for triggers but I never recommend over-documenting or elimination diets or anything like that to source out a possible trigger. These approaches may provoke undue stress, which may, in and of itself cause more headaches.

Can headaches be prevented?

Yes! In fact one of the most important things we do for treatment is to put people on a preventive agent for headaches. This is usually the single most important aspect of headache management. Some headaches can be curtailed by managing sleep, mood and eating regular meals, and these measures are very important. But many people need something more to get things under control.

Another very important point is that treating headaches reactively with over-the-counter medications too often and using opiates can make things worse and cause a medication-overuse headache. Getting on board with prevention is even more important given this issue.

If headaches are so common, it’s hard to know when to be concerned about them. When should someone seek medical help?

There are some things that indicate you see a doctor. The most important things are:

  • When a headache starts and its intensity peaks in less than 1 minute or is essentially maximally severe at its onset. We call this a thunderclap headache and this needs investigation.
  • New headaches during pregnancy can sometimes need testing and should be discussed with your doctor.
  • When there is a well-established pattern of headache for years, and it suddenly changes.
  • When is it accompanied by a fever, chills or other systemic symptoms.

Find more information about headaches at:

Canadian Headache Society

American Headache Society

American Migraine Foundation

About the author


Alexis Dobranowski

Alexis Dobranowski is a Communications Advisor at Sunnybrook.