Headache

By Mayo Clinic staff

• Definition
• Causes
• When to see a doctor

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Definition

Headache is pain in any region of the head. Headaches may occur on one or both sides of the head, be isolated to a certain location, radiate across the head from one point or have a vise-like quality. A headache may be a sharp pain, throbbing sensation or dull ache. Headaches may appear gradually or suddenly, and they may last less than an hour or for several days.

Causes

Your headache symptoms can help your doctor determine the cause and the appropriate treatment. Most headaches aren't the result of a serious illness, but some may result from a life-threatening condition requiring emergency care.

Headaches are generally classified by cause:

Primary headaches
A primary headache is caused by dysfunction or overactivity of pain-sensitive features in your head. A primary headache isn't a symptom of an underlying disease. Chemical activity in your brain, the nerves or blood vessels of your head outside your skull, or muscles of your head and neck — or some combination of these factors — may play a role in primary headaches. Some people may carry genes that make them more likely to develop such headaches.

The most common primary headaches are:

There are other headache patterns that are generally considered types of primary headache but are less common. These headaches have distinct features, such as an unusual duration or pain associated with a certain activity. Although these headaches are generally considered primary, each of them could be a symptom of an underlying disease. These headaches include:

Some primary headaches can be triggered by lifestyle factors, including:

• Alcohol, particularly red wine
• Certain foods, such as processed meats that contain nitrates
• Changes in sleep or lack of sleep
• Poor posture
• Skipped meals
• Stress

Secondary headaches
A secondary headache is a symptom of a disease that can activate the pain-sensitive nerves of the head. Any number of conditions — varying greatly in severity — may cause secondary headaches. Sources of secondary headaches include:

Specific types of secondary headaches include:

When to see a doctor

Seek emergency care
A headache can be a symptom of a serious condition, such as a stroke, meningitis or encephalitis. Go to a hospital emergency room or call 911 or your local emergency number if you have a sudden, severe headache or a headache accompanied by:

• Confusion or trouble understanding speech
• Fainting
• High fever, greater than 102 F to 104 F (39 C to 40 C)
• Numbness, weakness or paralysis on one side of your body
• Stiff neck
• Trouble seeing
• Trouble speaking
• Trouble walking
• Nausea or vomiting (if not clearly related to the flu or a hangover)

Schedule a doctor's visit
See a doctor if you experience headaches that:

• Occur more frequently than usual
• Are more severe than usual
• Worsen or don't improve with appropriate use of over-the-counter drugs
• Prevent you from working, sleeping or participating in normal activities
• Cause you distress, and you would like to find treatment options that enable you to control them better

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