What is a headache? 

Headache is defined as pain in the head or upper neck. It is one of the most common locations of pain in the body and has many causes. 

How are headaches classified? 

Headaches have numerous causes, and in 2007 the International Headache Society agreed upon an updated classification system for headache. Because so many people suffer from headaches, and because treatment is sometimes difficult, the new classification system allows health care practitioners to understand a specific diagnosis more completely to provide better and more effective treatment regimens. 

There are three major categories of headaches: 

• primary headaches, 
• secondary headaches, and 
• cranial neuralgias, facial pain, and other headaches 

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; as many as 90% of adults have had or will have tension headaches. Tension headaches are more common among women than men. 

Migraine headaches are  the second most common type  of primary headache. An estimated 28 million people in  the United States (about 12% of the population) will experience migraine headaches. 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. An estimated 6% of men and up to 18% of women will experience a migraine headache. 

Cluster headaches are  a rare type  of primary headache, affecting 0.1% of  the population. An estimated 85% of cluster headache sufferers are men. The average age of cluster headache sufferers is 28-30 years of age, although headaches may begin in childhood. 

Primary headaches affect quality of life. Some people have occasional headaches that resolve quickly, while others are debilitated. Tension, migraine,  and cluster headaches are not life-threatening. 

What are secondary headaches? 

Secondary headaches are those that are due to an underlying structural problem  in the head or neck. There are numerous causes of this type of headache ranging from bleeding in the brain, tumor, or meningitis  and encephalitis. 

What are cranial neuralgias, facial  pain, and other headaches? 

Neuralgia means  nerve pain (neur= nerve + algia=pain). Cranial neuralgia describes a group  of headaches that occur because  the nerves in the  head and upper neck become inflamed  and are the source of the head pain. Facial pain and a variety of other causes for headache are included in this category. 

What causes tension headaches? 

While tension headaches are the most frequently occurring type of headache, their cause is not known.  The most likely cause is contraction  of the muscles that cover  the skull. When  the muscles covering  the skull are stressed, they may spasm and cause pain. Common sites include the base  of the skull where  the trapezius muscles  of the neck inserts,  the temple where muscles  that assist  the jaw to move are located, and the forehead. 

There is little research  to confirm the exact cause of tension headaches. Tension headaches occur because of physical or emotional stress placed on the body. Physical stress  that may cause tension headaches include difficult and prolonged manual labor, or sitting at a desk or computer for long periods  of time Emotional stress may also cause tension headaches by causing the muscles surrounding the skull to contract.