A headache or cephalgia is defined as "a pain or ache in the head...It accompanies many diseases and conditions, including emotional distress."1
Headaches are one of the most common ailments, with most people experiencing a headache at some point in their life.2 They can affect anyone regardless of age, race and gender.
The World Health Organization (WHO) reports that around 47% of adults worldwide will have experienced a headache within the last year. As well as being symptoms of other conditions, headache disorders can lead to the development of other illnesses. Depression is three times more common in individuals with severe headaches than in healthy people.3
Contents of this article:
You will also see introductions at the end of some sections to any recent developments that have been covered by MNT's news stories. Also look out for links to information about related conditions.
Fast facts on headaches
Here are some key points about headaches. More detail and supporting information is in the main article.
- Headaches can be stand alone illnesses or the symptom of another condition.
- Depending on the specific type of headache, they can last for any time between a few hours and several weeks.
- Primary headaches are caused by dysfunction or overactivity in pain-sensitive structures in the head.
- The most common form of primary headache is the tension-type headache.
- A wide variety of conditions can cause secondary headaches, ranging from hangovers to brain tumors.
- The most common form of secondary headache is the rebound headache (medication-overuse headache).
- Health care providers will usually diagnose a headache from a history and description of its symptoms.
- The most common suggested treatment for headaches is rest and pain relief medication.
- Overuse of pain medication can lead to the development of rebound headaches.
- It is estimated that 50% of people experiencing headaches self-treat rather than see a health care provider.
What is a headache?
The pain from tension-type headaches have been described as "vise-like."
Headache is a broad term that encompasses many different things. Headaches are pains that occur in any region of the head; they can occur on both sides the head or be isolated to a certain location.
Headaches can radiate across the head from a central point or have a pincering vise-like quality. They can be sharp, throbbing or dull, appear gradually or suddenly and last for multiple days or less than an hour.4
There are multiple ways to define headaches. The International Headache Society (IHS) categorize headaches as primary headaches or secondary headaches, depending on what has caused them.5
Causes of headaches5,6
We will look at the causes of primary headaches and secondary headaches in turn.
1) 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.
Primary headaches can occur when pain-sensitive structures in the head do not work properly.
Common primary headaches include migraines, cluster headaches and tension headaches.
Some types of headache can be both primary and secondary as they may be an isolated issue or a result of another condition or illness. Such headaches can involve:
- Direct physical stimuli, such as temperature and external pressure
- Pain over the scalp (epicranial)
- Physical exertion
- Other miscellaneous headaches.
2) Secondary headaches
Secondary headaches are headaches that are symptoms of another condition that stimulates the pain-sensitive nerves of the head. There are a vast number of different conditions that can cause secondary headaches, ranging in severity from an alcohol-induced hangover to a brain tumor.
Secondary headaches can be the result of serious conditions such as stroke, but can equally be a consequence of eating cold food too quickly.
In addition to those two examples, the following list should serve to illustrate the variety of different conditions that can cause secondary headaches:
- Blood clots
- Brain freeze (ice cream headaches)
- Carbon monoxide poisoning
- Overuse of pain medication (rebound headaches)
- Panic attacks
As headaches can be a symptom of a serious condition, it is important to seek medical advice if headaches become more severe, regular or persistent.
For example, if the 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, a health care provider should be contacted.
Recent developments on headache causes from MNT news
The term "headbanging," does not sound particularly healthy, but can any medical harm come from rocking out in time to the music at a concert using a "violently rhythmic movement of the head"? The case of a Motörhead fan published in The Lancet suggests it can.
In 2009, 10% of males and 22% of females in the US reported experiencing migraines or severe headaches, according to the Centers for Disease Control and Prevention. Now, a new study suggests older individuals who suffer from migraines may be more likely to have silent brain injury and have double the odds of experiencing "silent strokes," compared with those who do not have migraines.
Whether a result of our work, home or social lives, all of us go through stressful periods. Now, new research has linked high-stress levels to an increased occurrence of headaches - an association that has long been suspected.
On the next page we look at the symptoms and diagnosis of headaches. On the final page we discuss treatments and therapies for headaches.