A Brief Account of the Headache Disorders of Public-health Importance


Headache is felt, at some time, by nearly everybody. As a symptom, it is a recurrent and painful feature of a number of headache disorders. Almost half the world's adults have recent personal experience of one or more of the common headache disorders.

Headache disorders

Headache disorders are real and often lifelong illnesses.

Two in particular – migraine and tension-type headache – are widespread and common. Together with medication-overuse headache, they are of major public-health importance: collectively, they are the 3rd highest cause of disability in populations throughout the world.


This almost certainly has a genetic basis, but environmental factors play a role in how it affects those who have it. The mechanism of migraine, deep in the brain, involves release of pain-producing inflammatory substances around the nerves and blood vessels of the head. Why this happens periodically to cause migraine attacks, and what brings the attacks to an end, are not known.

Migraine usually starts at puberty and, once it has begun, recurs throughout life. Adults with migraine describe disabling attacks in which headache and nausea are the key features. Vomiting may also occur, and many people are bothered by even normal levels of light and sound. The headache, typically one-sided and pulsating, is usually bad – sometimes very bad indeed – and made worse by any physical activity. It lasts for hours, up to 2–3 days. Attacks happen, on average, once or twice a month, but in some people much less (once a year) and in others much more (once a week). Often this is subject to lifestyle and environmental factors that suggest people with migraine react badly to changes in routine.

The visual disturbances of migraine (flashing lights and blind spots) are part of migraine aura. When these happen, they usually come before the headache starts. Although they are often thought of as an essential feature of migraine, in reality they are not. Only one third of people with migraine experience them, and not in every attack.

Effective treatments exist. Lifestyle modifications can help greatly in reducing frequency of attacks. A range of medications, including simple analgesics, anti-emetics and specific anti-migraine drugs (triptans), used correctly, can relieve or abort attacks. A number of prophylactic drugs, taken daily, can reduce attack frequency when other measures are inadequate.

Tension-type headache

The mechanism of this disorder is poorly understood. It has long been regarded as a headache with muscular origins, but this may not be entirely correct. It may be stress-related, or associated with musculoskeletal problems in the neck.

Tension-type headache takes a highly variable course, often beginning during the teenage years and becoming most troublesome in the 30s. This headache is usually mild or moderate, and described as pressure or tightness, like a band around the head. Sometimes it spreads into or from the neck. It lacks the specific features and associated symptoms of migraine.

There are distinct sub-types. Very large numbers of people have episodic tension-type headache in which headache occurs, as in migraine, in attack-like episodes. These usually last no more than a few hours but can persist for several days. They can be infrequent or frequent. Chronic tension-type headache is less common, but is present on more days than not, and sometimes every day without relief over long periods. This variant is much more disabling.

Simple analgesics, used correctly, are effective against episodic tension-type headache. These should not be used when attacks are very frequent (more than twice a week), or in chronic tension-type headache, as to do so would risk the development of medication-overuse headache (see below). Instead, a prophylactic medication should be taken daily as a preventative. When stress is a factor, psychological therapies can be very beneficial. When musculoskeletal problems are apparent in the neck, physiotherapy may be helpful.

Medication-overuse headache

Excessive use of medication to treat headache is the cause of this disorder. It is therefore wholly avoidable.

A typical history begins with episodic headache – migraine or tension-type headache. This is treated with an analgesic or other medication for each attack. Over time, headache episodes become more frequent, as does medication intake. This happens over a few weeks or much, much longer. A common and probably key factor at some stage in the development of medication-overuse headache is a switch to pre-emptive use of medication, in anticipation of headache and with a natural wish to prevent it.

All medications for the treatment of headache, in overuse, are associated with this problem. Frequency of use is important: even when the total quantities are similar, low daily doses carry greater risk than larger weekly doses.

Medication-overuse headache is oppressive, debilitating and persistent, although often at its worst on awakening in the morning. In the end-stage, which not all patients reach, headache persists all day, fluctuating with medication use repeated every few hours. This is highly disabling.

Treatment of medication-overuse headache is first and foremost by withdrawal of the overused medication. This requires supervision, as symptoms may be expected to worsen before they improve. Although success is usual, medication-overuse headache is better avoided in the first place by public education.

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