But this would be asking too much of you, as a patient. If the cause of your headache is not obvious - as it is when you have a hangover - it is unlikely that you will be able to identify the type of headache you suffer from. This is why, if you suffer from repeated or persistent headaches, you should consult a doctor. What is important is that you give him as much detail as possible.

One IHS differentiation which is obvious and easy for all of us to make is the basic division of headache types into two major groups - primary and secondary or symptomatic headaches.

Primary headaches are all those which do not have another medical condition as their cause. The headache is the actual (primary) disorder itself.
Secondary headaches on the other hand are all those which do not occur "of their own accord" but are caused by another condition. Secondary headaches are also caused by concussion, impaired blood circulation in the brain or a cerebral haemorrhage, by thrombosis of the cerebral veins or even by a brain tumour, but also by inflammation of the eyes and ears, and by frontal and maxillary sinusitis and dozens of other diseases.

Secondary headaches may also be expected when certain substances are consumed: in addition to alcohol, these may include caffeine and nicotine and also nitrites used to preserve meat, fish and sausages and the flavour enhancer monosodium glutamate, which is used in Asian cooking.

Although these types of secondary headache account for well over 100 of the headache types in the IHS classification, 90 per cent of all headache patients suffer from three different types of primary headache: tension-type headaches, cluster headaches and migraine.