Pain in any region of head including forehead, above ears, behind the head or even in the neck region is medically regarded as ‘headache’. They are one of the most common medical complaints and can affect anyone regardless of age, gender and physical condition.
According to the World Health Organization (WHO), almost half of the adults worldwide experience headache at least once in a year. There are different types and causes of headache of which tension headaches are most common.
According to the International Headache Society (HIS), headaches are broadly classified into two types: Primary and Secondary. Primary headache occur without any other symptoms while Secondary headaches are accompanied by the symptoms of some other disease.
To simplify what primary and secondary headaches are, it is important to note that migraine is a primary headache while headache resulting from an infection, head injury or brain tumor, is secondary headache. Primary headaches can occur more common and can cause pain and disability on a regular basis, but they are not considered dangerous.
The most common types of primary headaches include migraines and tension-type headaches. Primary headaches affects almost 21.8 percent of population and occur when the individuals are between 20-40 years of age.
Migraines are characterized by pulsing head pain, nausea, sensitivity to light and sound. While tension-type headaches are specified by a feeling of pressure on both sides of head. There are other types of primary headaches as well, which mainly includes the Cluster Headaches (15-180 minutes episodes of headache), Face Pain (Medically termed as Trigeminal Neuralgia) and Primary Cough Headache.
Headaches may also be caused by the problems other than in the head or neck region, in this case named as Secondary Headaches. Most serious cases of such headaches include pain arising due to bleeding in the brain (intracranial hemorrhage), due to brain tumors and also due to the continuous pressure on the eyeball (acute closed angle glaucoma). Gastrointestinal problems and inflammation in blood vessels and joints may also cause pain in the head and neck region.
How brain sense headache?
How does this pain arise and how is our brain able to sense it as pain? The human brain is insensitive to pain because it lacks the pain receptors, but some areas of head and neck do have pain receptors. The Pial Arteries, which actually penetrate into the brain tissue, are responsible for pain production.
Headaches often result from the irritation of the meninges (layers of specific tissue surrounding the brain) or blood vessels. Inflammation, dilation or muscular tension generate a signal and stimulate the nociceptors (receptors that sense pain). Once the nociceptors are stimulated, they send a signal to the brain via the nerves and signals that a part of body hurts.
Primary headaches are more difficult to understand and the mechanism behind them is still unknown. Previously, migraines were thought to be caused by a problem with the blood vessels in the brain area but this vascular theory is no more accepted. Currently it is thought that migraines are caused by the primary problems in the nerves present in the specific region of brain.
Treatment for the different types of headache involve different strategies. Treatment for primary headaches usually involve the use of different drugs while that of secondary headache involves treating the underlying cause.