Headaches are extremely common and can take many forms, from mild to debilitating, lasting from minutes to days. When the skull is in pain, it is thought that the brain tissue itself must be in pain. But that’s not likely.
The brain senses pain from the whole body, but it doesn’t have its own pain receptors. So why do we get a headache?
Headaches can stem from an underlying medical condition, such as swollen sinuses, low blood sugar, or a head injury. But generally speaking, most headaches arise due to “referred pain”, which means that if you feel the pain in a different place from where it is actually occurring, he told live science Charles Clarke, a neurologist and headache specialist at Vanderbilt Health in Tennessee.
It’s similar to what happens with a herniated disc in your back, which can cause sciatica, a pain in your leg. In most cases, when you get a headache, a problem somewhere in the body – in the jaw, shoulders or neck – causes pain in the muscles and nerves around the brain, he explained.
Tension headaches are the most common type of recurring headaches, which according to the World Health Organization. Tension headaches often occur as pain in the muscles at the top of the head or forehead, Clarke said.
The pain is caused by tight muscles in the face, neck and scalp and may be related to stress, according to the British National Institute of Health (NIH). But the pain in the head and the tightening of the cranial muscles can be secondary to another stress responselike shoulders or a tight jaw, he added.
According to the NIH, pain-sensitive nerves in the muscles and blood vessels around the head, neck, and face can be triggered by different processes, such as enlarged blood vessels, stress, or muscle tension. Once activated, they send messages to the brain, but it can feel as if the pain is coming from deep within the brain tissue.
To the migraines are another kind of headache. They can be felt in different ways and in different areas: deep pain or superficial pain; on the back, left or right of the head, or behind the eyes. What distinguishes migraines is their severity – they are more intense than other pains and can last longer.
It is often genetic and can cause additional symptoms such as nausea. The underlying causes are not fully understood, but it is theorized that it is linked to the trigeminal nerve and the dura mater, the protective layer of the brain where blood vessels expand and contract.
One possible explanation for migraines is that an electrical event in the brain stimulates the trigeminal nerve pathways and triggers an inflammatory reaction. Inflammation spreads through hard blood vessels and nerve fibers from the trigeminal nerve send signals back to the brainstem. A inflammation spreads to pain-sensitive meninges, triggering a headache.
This cascade of inflamed blood vessels and irritated nerves is “a fire that’s burning out of control,” Clarke said. It’s like a ‘feedback’ loop that becomes more and more irritable, triggering a migraine.
Although the relationships between pain around the body and headache are established, the mechanisms that cause headaches are still not fully understood, added the neurologist.
The good news is that “we are very good at treating them”, continued the expert. Lifestyle changes; over-the-counter medications; and medications prescribed for more serious disorders can reduce their severity and frequency.
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