Headaches are one of the most common medical complaints; most people experience them at some point in their life. They can affect anyone regardless of age, race, and gender.
The World Health Organisation (WHO) reports that almost half of all adults worldwide will experience a headache in any given year.

A headache can be a sign of stress or emotional distress, or it can result from a medical disorder, such as migraine or high blood pressure, anxiety, or depression. It can lead to other problems.
People with chronic migraine headaches, for example, may find it hard to attend work or school regularly.

Causes:
Headache is a common complaint worldwide.
A headache can occur in any part of the head, on both sides of the head, or in just one location.

There are different ways to define headaches.

The International Headache Society (IHS) categorize headaches as primary, when they are not caused by another condition, or secondary, when there is a further underlying cause.

Primary headaches :
Primary headaches are stand-alone illnesses caused directly by the overactivity of, or problems with, structures in the head that are pain-sensitive.

This includes the blood vessels, muscles, and nerves of the head and neck. They may also result from changes in chemical activity in the brain.

Common primary headaches include migraines, cluster headaches, and tension headaches.

Secondary headaches:
Secondary headaches are symptoms that happen when another condition stimulates the pain-sensitive nerves of the head. In other words, the headache symptoms can be attributed to another cause.

A wide range of different factors can cause secondary headaches.

These include:

alcohol-induced hangover
brain tumor
blood clots
bleeding in or around the brain
“brain freeze,” or ice-cream headaches
carbon monoxide poisoning
concussion
dehydration
glaucoma
teeth-grinding at night
influenza
overuse of pain medication, known as rebound headaches
panic attacks
stroke

As headaches can be a symptom of a serious condition, it is important to seek medical advice if they become more severe, regular, or persistent.

For example, if a headache is more painful and disruptive than previous headaches, worsens, or fails to improve with medication or is accompanied by other symptoms such as confusion, fever, sensory changes, and stiffness in the neck, a doctor should be contacted immediately.

Types:

Tension headaches
Eating something very cold can lead to a “brain freeze.”
Tension headaches are the most common form of primary headache. Such headaches normally begin slowly and gradually in the middle of the day.

The person can feel:

as if they have a tight band around the head
a constant, dull ache on both sides
pain spread to or from the neck
Tension-type headaches can be either episodic or chronic. Episodic attacks are usually a few hours in duration, but it can last for several days. Chronic headaches occur for 15 or more days a month for a period of at least 3 months.

Migraines :
A migraine headache may cause a pulsating, throbbing pain usually only on one side of the head. The aching may be accompanied by:

blurred vision
light-headedness
nausea
sensory disturbances known as auras
Migraine is the second most common form of primary headache and can have a significant impact on the life of an individual. According to the WHO, migraine is the sixth highest cause of days lost due to disability worldwide. A migraine can last from a few hours to between 2 and 3 days.

Rebound headaches
Rebound or medication-overuse headaches stem from an excessive use of medication to treat headache symptoms. They are the most common cause of secondary headaches. They usually begin early in the day and persist throughout the day. They may improve with pain medication, but worsen when its effects wear off.

Along with the headache itself, rebound headaches can cause:

neck pain
restlessness
a feeling of nasal congestion
reduced sleep quality
Rebound headaches can cause a range of symptoms, and the pain can be different each day.

Cluster headaches:
Cluster headaches usually last between 15 minutes and 3 hours, and they occur suddenly once per day up to eight times per day for a period of weeks to months. In between clusters, there may be no headache symptoms, and this headache-free period can last months to years.

The pain caused by cluster headaches is:

one-sided
severe
often described as sharp or burning
typically located in or around one eye
The affected area may become red and swollen, the eyelid may droop, and the nasal passage on the affected side may become stuffy and runny.

Thunderclap headaches:
These are sudden, severe headaches that are often described as the “worst headache of my life.” They reach maximum intensity in less than one minute and last longer than 5 minutes.

A thunderclap headache is often secondary to life-threatening conditions, such as intracerebral hemorhage, cerebral venous thrombosis, ruptured or unruptured aneurysms, reversible cerebral vasoconstriction syndrome (RVS), meningitis, and pituitary apoplexy.

People who experience these sudden, severe headaches should seek medical evaluation immediately.

Diagnosis:
A doctor will usually be able to diagnose a particular type of headache through a description of the condition, the type of pain, and the timing and pattern of attacks. If the nature of the headache appears to be complex, tests may be carried out to eliminate more serious causes.

Further testing could include:

blood tests
X-rays
brain scans, such as CT and MRI
The WHO points out that headaches are often not taken seriously because they are sporadic, most headaches do not lead to death, and they are not contagious.

They call for more resources to be allocated for the treatment of headache disorders, because of the huge health burden they represent.

Symptoms:
Headaches can radiate across the head from a central point or have a vise-like quality. They can be sharp, throbbing or dull, appear gradually or suddenly. They can last from less than an hour up to several days.

The symptoms of a headache depend to some extent on what type of headache it is.

Tension headache: There may be general, mild to moderate pain that can feel like a band around the head. They tend to affect both sides of the head.

Migraine headache: There is often a severe throbbing pain in one part of the head, often the front or the side. There may be nausea and vomiting, and the person may feel especially sensitive to light or noise.

Cluster headaches: These can cause intense pain, often around one eye. They usually happen around a particular time of year, possibly over a period of 1 to 2 months.

Treatment:
The most common ways of treating headaches are rest and pain relief medication.

Generic pain relief medication is available over the counter (OTC), or doctors can prescribe preventative medication, such as tricyclic antidepressants, serotonin receptor agonists, anti-epileptic drugs, and beta-blockers.

It is important to follow the doctor’s advice because overusing pain relief medication can lead to rebound headaches. The treatment of rebound headaches involves the reducing or stopping pain relief medication. In extreme cases, a short hospital stay may be needed to manage withdrawal safely and effectively.