Types of Headache: Facts and Figures

The International Headache Society has now published its second edition of the Classification of Headaches and this describes each type of headache known to medicine. It is intended for use by doctors and physicians as a reference point when diagnosing and treating people who come to them with a headache as one of their main symptoms.

The international headache classification includes three overall categories of headache – primary headaches, secondary headaches and a catch-all for all other types including facial pain, neuralgia and eye pain.

Headaches Classed as Primary

Primary headaches are defined as a headache that occurs as the main symptom and has no apparent cause, such as a brain tumour. Headaches that occur because they are related to another illness are called secondary headaches.

Primary headaches include migraine and tension headaches, one of the two most common types experienced by people all over the world. In this category are also cluster headaches, primary headaches brought on by cough, exertion, sexual intercourse, daily persistent headache and primary thunderclap headache.

Each of these categories is then split into sub groups to make diagnosis easier. So, for example, migraine is split into migraine that is accompanied by an aura, migraine with no aura, retinal migraine, silent migraine (migraine symptoms without head pain) and probable migraine. Tension headaches have four sub categories depending on how often they are experienced. Frequent tension type headaches are defined as causing 10 headaches on 15 or more days each month for a period of at least three months.

Headaches Classed as Secondary

Secondary headaches are known to be associated with a definite cause such as an injury to the head or neck, a problem with the spine, or due to substance abuse or withdrawal symptoms, infection or tumour, for example. Secondary headaches are also then split into several sub types; headaches due to infection can either be due to an infection within the skull itself, an general infection in the body, it can be due to HIV/AIDS or it can occur as a symptom after the infection has cleared but the body is affected by problems related to the immune response to that infection.

Headaches in the Other Category

There are a large number of headaches in this grouping – and most are headaches due to a problem with the nerves, either in the spine, the face or the head. It includes the pain caused by trigeminal neuralgia – where the trigeminal nerve that carries signals across various parts of the face, becomes inflamed, causing bad face and head pain. Also listed are headaches that come on when someone eats a very cold food such as ice cream, or drinks an ice cold drink. It is often called an ice cream headache.

Definite, Chronic or Probable Headaches

All of the types of headache described in the classification can be either chronic – it continues for a long period of time despite treatment and despite the underlying illness clearing up. A probable diagnosis of any particular headache type is based on the symptoms noted when the person experiencing the headaches is examined and their case history is taken. It only becomes a definite diagnosis when that person responds well to the treatment that is given. If the treatment for migraine, for example, reduces the frequency and intensity of the headaches, this is taken as a positive sign that the headaches being experienced are definitely migraines. The success of the treatment ‘proves’ the diagnosis was right.

The View of the World Health Organisation

The World Health Organisation accepts the classification of headaches put forward by the International Headache Society that was last revised in 2004. It recognises headaches as a common problem that affects a large number of people throughout the world, causing great suffering to people and their families, economic losses for individuals, communities and nations and a significant cost to healthcare services.