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A headache is a pain in the head. Approximately seven of 10 people get headaches. A headache may be located in any part of the head and may even extend to the neck. The problem can be acute (short and isolated) or chronic (a common occurrence). Most headaches are painful and annoying but can be easily relieved with aspirin or acetaminophen. However, in some cases head pain becomes severe and debilitating, and occasionally a headache is a symptom of a serious underlying medical problem. The most common types are tension headaches and migraines.

Causes

Tension headaches are traditionally attributed to tensing of the facial, scalp or neck muscles, while migraine pain is associated with alternate constriction and relaxation of blood vessels in the brain. While these factors indeed have a role in headache pain, in recent years researchers have also focused attention on alterations in nerve pathways and imbalances in brain chemistry. The trigeminal nerve system seems to be a major pain pathway for headaches; serotonin, a neurotransmitter or nerve chemical, regulates pain messages passing through the trigeminal nerve system. A malfunction or chemical imbalance in this system is believed to be an underlying cause of headaches.

Types of Headaches

It is important first to separate primary headaches from secondary headaches (those caused by another medical condition, such as a tumor). Primary headaches are common and tension headaches and migraines; other types include cluster headaches, sinus headaches and rebound headaches.

Tension headaches are the most common primary headache. They are characterized by a feeling of dull pain that affects the entire head. The pain is typically described as a tightness or bandlike constriction, which is usually dull and does not throb. Tension headaches are commonly triggered by stress, fatigue, depression or anxiety. Other causes include excessive alcohol or caffeine use, excessive smoking, eye strain, overexertion, colds or flu, and working for an extended period with the head held in one position (as at a computer).

Migraine headaches are characterized by throbbing pain that commonly begins on one side of the head. Some are preceded by fatigue, depression or an aura (an unusual sensation that may consist of tingling or numbness, strange tastes or odors, restlessness, confusion, or visual disturbances, such as seeing flashing lights). Migraine attacks occur on a sporadic basis and may last several hours to several days. Their pain may become disabling. In addition, there may be other symptoms, such as nausea, vomiting, dizziness, chills, loss of appetite, irritability, fatigue, and sensitivity to light and sound. These headaches may be triggered by factors such as hormonal fluctuations (including premenstrual syndrome), allergic reactions, stress, foods that contain the amino acid tyramine (such as red wine, aged cheese and smoked fish), chocolate, food additives, bright lights and loud noises. Migraines run in families, and women are three times more likely to have them than are men.

Cluster headaches are rare and intensely painful. They are characterized by burning or boring pain that generally occurs at night, waking a person from sleep. Pain is usually located behind or around one eye. Cluster headaches tend to occur in groups or clusters for a period of time (which can be as short as days or as long as months) and then disappear. They may or may not return at a later time. This type of headache affects primarily men, especially heavy smokers.

A sinus headache may develop when the sinuses become infected or inflamed. Pain typically comes on quickly in the nasal area and worsens over time. A sinus headache usually follows a bad cold and is accompanied by a fever. While many people have head pain in the area of the sinuses, most do not have sinus headaches; these are usually migraine or tension headaches.

Rebound headaches may develop when a person takes medication for headaches more than two or three times a week. When analgesics are overused to treat headaches, the body adapts and grows dependent on them. Rebound headaches may vary in timing and intensity, but can occur as often as daily. There may be nearly constant low-grade pain, with occasional episodes of more intense pain.

Diagnosis and Treatment

Doctors advise people who have chronic or severe headaches to seek prompt medical evaluation and treatment. Diagnosis of headache type is based on the nature of the pain, its frequency and duration, location, severity and accompanying symptoms. Tests such as CT scanning (computed tomography scanning) and MRI (magnetic resonance imaging) may be performed to rule out any serious underlying causes of symptoms, such as a ruptured aneurysm, brain tumor or temporal arteritis.

Home care for mild-to-moderate headaches includes rest, ice or heat packs, hot showers, massage, and over-the-counter pain relievers, such as aspirin, acetaminophen or ibuprofen. To prevent rebound headaches, only the minimal necessary dose of medication should be taken. Doctors recommend strategies such as exercise, meditation, relaxation therapy and biofeedback to control stress. People who have migraines benefit from napping in a dark, quiet room.

It is also important to identify and avoid the triggers of headaches (such as alcohol, caffeine, smoking and certain foods). This is particularly important in the case of migraine headaches. To identify triggers, it is useful to maintain a headache diary (a calendar record of headaches, associated symptoms, and environmental factors, such as diet, menstrual cycles and sleep patterns).

Doctors treat chronic or severe headaches with two categories of medications: abortive (to relieve pain and other symptoms) and prophylactic (to prevent headaches from developing). Abortive medications include triptans (such as sumatriptan and zolmitriptan), vasoconstrictors (such ergotamine tartrate), lidocaine nasal drops, muscle relaxants, narcotic analgesics, and aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs). Prophylactic medications include tricyclic antidepressants, serotonin antagonists, cardiovascular drugs (beta blockers and calcium channel blockers), antiseizure drugs (such as valproic acid), riboflavin (vitamin B2), and magnesium. Preventive medication is usually recommended only for people who have frequent attacks and for people in whom headaches are so severe that they prevent normal activity. For sinus headaches, doctors recommend use of decongestants or antibiotics and in some cases draining the affected sinus. Because serious complications may develop, headaches resulting from temporal arteritis (a type of arterial inflammation) require careful medical evaluation and treatment with corticosteroid medications. A person who has rebound headaches must be weaned from reliance on analgesics. This process is easier under a doctor’s supervision, as he or she can recommend treatments to help with drug withdrawal. Any medical conditions that underlie headaches (for example, depression, anxiety or other emotional problems) also require appropriate treatment.

Excerpted from: Complete Medical Encyclopedia, American Medical Association, 2003.

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