Headache

Overview

Headache is a term used to describe aching or pain that occurs in one or more areas of the head, face, mouth, or neck. Headache can be chronic, recurrent, or occasional. The pain can be mild or severe enough to disrupt daily activities. Headache involves the network of nerve fibers in the tissues, muscles, and blood vessels located in the head and at the base of the skull.

Types
Primary headache accounts for about 90% of all headaches. There are three types of primary headache: tension headache, cluster headache, and migraine.

Tension headache is the most common type of primary headache. Episodes usually begin in middle age and are often associated with the stresses, anxiety, and depression that can develop during these years.

Cluster headaches occur daily over a period of weeks, sometimes months. They may disappear and then recur during the same season in the following year.

Secondary headache is associated with an underlying condition such as cerebrovascular disease, head trauma, infection, tumor, and metabolic disorder (e.g., diabetes, thyroid disease). Head pain also can result from syndromes involving the eyes, ears, neck, teeth, or sinuses. In these cases, the underlying condition must be diagnosed and treated. Also, certain types of medication produce headache as a side effect.

Severe, sudden, and debilitating secondary headache that develops after a blow to the head, that interferes with normal activity, or that accompanies other symptoms (e.g., convulsions, disorientation, dizziness, loss of consciousness, pain in the eye or ear, fever) should be evaluated by a physician as soon as possible.

Incidence and Prevelence
In the United States, over 45 million people—including more than the 33 million sufferers of asthma, diabetes, and heart disease—experience chronic, recurring headaches. Of these, 28 million suffer migraine every year.

Approximately 75% to 90% of all persons who complain of chronic or frequent headaches suffer from tension headache. Tension headache is more prevalent among women than men. Cluster headaches primarily affect men between the ages of 20 and 40.

Causes

Tension headaches are caused by stress, muscular tension, vascular dilation, postural changes, protracted coughing or sneezing, and fever. Physical and mental conditions that can lead to chronic muscular tension and headache include:

Anxiety
Arthritis in neck or spine
Degenerative bone or disk disease in the neck or spine
Depression
Temporomandibular joint disorders
There are several well-known triggers associated with cluster headaches, including drugs that dilate or constrict blood vessels and alcohol. This suggests that changes in the walls of blood vessels in the head may be partly responsible.
Some researchers believe that a low level of endorphins may cause frequent, severe, or chronic headache pain. Endorphins are painkilling compounds found in the brain