Headache

What is a Headache?

Headache is defined as a pain arising from the head or upper neck of the body. The pain originates from the tissues and structures that surround the skull or the brain because the brain itself has no nerves that give rise to the sensation of pain (pain fibers). The thin layer of tissue (periosteum) that surrounds bones, muscles that encase the skull, sinuses, eyes, and ears, as well as thin tissues that cover the surface of the brain and spinal cord (meninges), arteries, veins, and nerves, all can become inflamed or irritated and cause headache. The pain may be a dull ache, sharp, throbbing, constant, intermittent, mild, or intense.

How are headaches classified?

In 2013, the International Headache Society released its latest classification system for headache. Because so many people suffer from headaches, and because treatment is difficult sometimes, it was hoped that the new classification system would help health-care professionals make a more specific diagnosis as to the type of headache a patient has, and allow better and more effective options for treatment.

The guidelines are extensive and the Headache Society recommends that health-care professionals consult the guidelines frequently to make certain of the diagnosis.

There are three major categories of headache based upon the source of the pain.

Primary headaches
Secondary headaches
Cranial neuralgias, facial pain, and other headaches
The guidelines also note that a patient may have symptoms that are consistent with more than one type of headache, and that more than one type of headache may be present at the same time.

Quick Guide
Migraine or Headache? Migraine Symptoms, Triggers, Treatment
Migraine or Headache? Migraine Symptoms, Triggers, Treatment
Migraine Triggers
A migraine is a throbbing painful headache, usually on one side of the head, that is often initiated or "triggered" by specific compounds or situations (environment, stress, hormones, and many others). They occur more often in women (75%, approximately) and may affect a person's ability to do common tasks.

Migraine headaches are often triggered to occur when the person is exposed to a specific set of circumstances.

flashing lights
anxiety and stress
lack of food or sleep
hormonal changes
foods (red wine, cheese, chocolate, soy sauce, processed meat, and MSG)
tyramine
caffeine

What are primary headaches?
Primary headaches include migraine, tension, and cluster headaches, as well as a variety of other less common types of headache.

Tension headaches are the most common type of primary headache. Tension headaches occur more commonly among women than men. According to the World Health Organization, 1 in 20 people in the developed world suffer with a daily tension headache.
Migraine headaches are the second most common type of primary headache. Migraine headaches affect children as well as adults. Before puberty, boys and girls are affected equally by migraine headaches, but after puberty, more women than men are affected.
Cluster headaches are a rare type of primary headache. It more commonly affects men in their late 20s though women and children can also suffer from this type of headache.
Primary headaches can affect the quality of life. Some people have occasional headaches that resolve quickly while others are debilitating. While these headaches are not life threatening, they may be associated with symptoms that can mimic strokes.

Many patients equate severe headache with migraine, but the amount of pain does not determine the diagnosis of migraine. Read our Migraine Headache article for more information about the symptoms, causes, and treatment of migraines.

What are secondary headaches?
Secondary headaches are those that are due to an underlying structural or infectious problem in the head or neck. This is a very broad group of medical conditions ranging from dental pain from infected teeth or pain from an infected sinus, to life-threatening conditions like bleeding in the brain or infections like encephalitis or meningitis.

Traumatic headaches fall into this category including post-concussion headaches.

This group of headaches also includes those headaches associated with substance abuse and excess use of medications used to treat headaches (medication overuse headaches). "Hangover" headaches fall into this category as well. People who drink too much alcohol may waken with a well-established headache due to the effects of alcohol and dehydration.


What are cranial neuralgias, facial pain, and other headaches?
Neuralgia means nerve pain (neur=nerve + algia=pain). Cranial neuralgia describes inflammation of one of the 12 cranial nerves coming from the brain that control the muscles and carry sensory signals (such as pain) to and from the head and neck. Perhaps the most commonly recognized example is trigeminal neuralgia, which affects cranial nerve V (the trigeminal nerve), the sensory nerve that supplies the face and can cause intense facial pain when irritated or inflamed.