There are more than 200 in the International Headache Society classification! They can be divided in 2 categories: primary headaches and secondary headaches. For instance, migraine is a primary headache.

All headaches are caused by the activation of brain areas that process pain signals from the head and the neck.

A secondary headache is caused by a lesion (damage) which activates these brain regions by stimulating nerves that detect pain (for example, a tumour, sinusitis or meningitis). It can also be caused by a metabolic imbalance that activates the pain systems (for example sleep apnea that may cause morning headaches).

A primary headache is caused when, in the brain, regions responsible for pain are activated without a lesion. These brain regions themselves are unstable, as if there were short-circuits triggering pain without damage as a cause. Primary headaches are neurological phenomena, like epileptic seizures, but fortunately they do not have direct consequences on physical health.

Primary headaches do not indicate a real danger, but they simulate it, which can cause a lot of distress.They also have a significant repercussion on function.

Tension headaches , migraines and cluster headaches are primary headaches. A headache related to meningitis is a good example of what a secondary headache is. Migraine is a frequent and incapacitating primary headache. A migraine attack is caused by an activation of brain regions responsible for pain signals from the head.

When you have a headache because of a substance (a hangover for instance, when you go through a slight alcohol withdrawal, or some medication), it is also a secondary headache. Even if headaches can sometimes make us worry about brain tumours, the vast majority of headaches are primary, and thus have no consequence on physical health.

A migraine sufferer can also be affected by a secondary headache. Often times, the person will be able to distinguish the two types of headaches, since secondary headaches may have distinct characteristics and sensations different from migraine attacks.