There are so many different types of headache that it can give you a headache in itself trying to pin down the cause of your own. In this piece, we will discuss the common categories of headaches and break it down, simply. 

Headaches can be primary or secondary. A secondary headache is one caused by something else, such as dehydration or an alcohol hangover. A primary headache means that the headache is produced independent of another cause. 
 
Secondary headaches can be caused by many things – dehydration, alcohol, viral infection, systemic infection, etc. A common cause of a secondary headache is a sinus infection. Usually, this headache is frontal and can be reproduced when the face is pressed (facial/sinus pain).

Secondary headaches can also be caused by a problem with the brain itself – such as brain swelling (cerebral oedema), a blockage in the drainage system (sinus venous thrombosis), a certain type of serious brain bleed (subarachnoid haemorrhage). 
To clear the headache, we need to correct the underlying cause. Dehydrated? Drink more water, easy peasy.
 
Primary headaches can be challenging to treat as the headache is independent of another cause. There are three main types of primary headache – migraines, cluster headaches, and tension headaches.
 
Migraines are very severe headaches. The pulsating pain will usually be localised in one area, but not always. The sufferer is usually sensitive to light. They are often nauseous and may experience blurred vision. Some migraines produce an ‘aura’. An aura is typically an odd visual phenomenon that will normally precede a migraine headache – they include flashing lights and zig-zag lines. Some people can even experience a visual aura with no headache whatsoever – this is still a migraine (if other causes are ruled out). 
Interestingly, migraines can cause almost any neurological symptom (including weakness, partial loss of vision, loss of sensation, etc.) that will resolve without any lasting damage. They can, of course, mirror other conditions such as an acute stroke – so prompt investigation may be necessary. 

The treatment for headaches tends to be tailored towards prophylaxis (fancy mumbo-jumbo that means prevention). These include beta-blockers, calcium-channel blockers (both usually used for high blood pressure); some antidepressants; even high-tech meds such as monoclonal antibodies (the expensive ones that are injected and end in “umab”).
During a migraine, medications such as high dose aspirin or a group of medications called the ‘Triptans’ may be beneficial – as well as avoiding any exacerbating triggers (such as light).
 
A cluster headache is an intense pain localised on one side of the head near the front, usually around the eye. It can sometimes affect the eye itself, altering pupil size and tearing up, which can cause a runny nose. The get their name from the frequency of attacks (can last between fifteen minutes to a few hours) that tend to come in clusters of weeks to months – followed by a period of remission.

Tension headaches are described as a band around your head, felt mostly in the front. They are typically caused by psychological stress, a lack of sleep, or from stimulants such as drinking too much coffee.
Caffeine is an interesting one, caffeine can help to treat a headache (often added to pain relievers such as 'Panadol Extra') but too much of it on a daily basis can cause headaches too! 

This strikes of the old adage - Everything in moderation - what a terrible truth!