There are many factors that cause a headache. To understand these causes, it is important to understand the types of headaches that can plague humans

Primary headaches occur commonly and the best examples are tension headaches, cluster headaches and migraines. The causes for these primary headaches are many.

The secondary headaches, on the other hand, are caused by underlying diseases. In the case of the latter, the primary illness has to be treated for the headache to disappear.

a) Tension headaches

These headaches are so named because they occur due to excessive stress, mostly after a hectic day. The sufferers always describe the headache as a band of pressure that goes in circles around the head. It often begins at the back of the head and the upper neck and occurs on both sides of the head (bilateral), with the pain peaking above the eyebrows.

Tension headaches are mild and do not prevent a person from going about their normal routine. They occur sporadically although it is known to affect some people quite frequently. They are not accompanied by an aura, nausea, and increased sensitivity to light and sound or vomiting.

b) Cluster headaches

These headaches tend to arrive in clusters or groups and may last for weeks or for months. This is then followed by pain-free periods, which may last up to months or years. During the period of headache, the pain may occur daily, sometimes even twice a day. In some individuals, it occurs more frequently.

Every episode of the headache lasts for 30 minutes to an hour and a half. They occur at the same time, each day, and are capable of waking a person from a sound sleep at night.

Typically the pain is located around or behind one eye (unilaterally). Some describe the pain as akin to a red -hot rod inside the eye. The afflicted eye turns red due to inflammation and also becomes watery. The nose on the affected side become runny and congested.

Individuals with cluster headaches tend to be restless. Several have been discovered pacing the floor or banging their heads against a wall .The pain can be quite severe and may drive the person to resort to desperate measures. These headaches are more prevalent in males than in females. What actually causes the headache is not known, but alcohol and cigarettes are known to precipitate the attack.

c) Coital/ exercise induced headaches

Certain middle- aged men experience this severe headache suddenly after sex. It may not last beyond 15 minutes. However, other more severe headaches have to be ruled out in these individuals with the help of a CT scan. Such headaches may also occur in a physically unfit person after physical exertion.

One must also remember that the popular tablet like like ‘Viagra’ - to enhance erections –can also give rise to headache.