Tension headache
Tension headaches,, are the most common type of headaches. The pain can radiate from the neck, back, eyes, or other muscle groups in the body. Nearly everyone will have at least one tension headache in their lifetime.




Frequency and duration
Tension headaches can be episodic or chronic. Episodic tension headaches are defined as tension headaches occurring less than 15 days a month, whereas chronic tension headaches occur 15 days or more a month for at least 6 months. Tension headaches can last from minutes to days or even months, though a typical tension headache lasts 4-6 hours.

Pain
Tension headache pain is often described as a constant pressure, as if the head were being squeezed in a vise. The pain is frequently bilateral which means it is present on both sides of the head at once. Tension headache pain is typically mild to moderate, but may be severe. In contrast to migraine, the pain does not increase during exercise.

Cause
The exact cause of tension headaches is still unknown. It has long been believed that they are caused by muscle tension around the head and neck. However although muscle tension may be involved, there are many forms of tension headaches and some scientists now believe there is not one single cause for this type of headache. One of the theories is that the pain may be caused by a malfunctioning pain filter which is located in the brain stem. The view is that the brain misinterprets information, for example from the temporal muscle or other muscles, and interprets this signal as pain. One of the main molecules which is probably involved is serotonin. Evidence for this theory comes from the fact that tension headaches may be successfully treated with certain antidepressants. Another theory says that the main cause for tension type headaches and migraine is teeth clenching which causes a chronic contraction of the temporalis muscle.

Treatment
Episodic tension headaches generally respond well to over-the-counter analgesics, such as acetaminophen or aspirin. However, these medications should be avoided in cases of chronic tension headache, due to the risk of rebound headaches. Chronic tension headaches are more difficult to treat. Suggested therapies include:

Swimming two to three times a week
Acupuncture
Biofeedback
Massage
heat pillow
relaxation techniques like:
Jacobson's Progressive Muscle Relaxation
autogenous training
The NTI Tension Suppression System
Amitriptyline
Doxepine
Imipramine

Tension headaches are exacerbated by states or activities that induce muscle tension, such as stress. Avoiding such states can lessen the frequency of tension headaches. Tension headaches can also be secondary to other conditions, such as an upper respiratory infection or other virus.

Often the best treatment for a mild tension headache that does not impair a person's ability to function is simple endurance. Many tension headache sufferers receive relief from sleep.

Prognosis
Tension headaches that do not occur as a symptom of another condition are painful and annoying, but not harmful. It is usually possible to receive relief from treatment. Tension headaches that occur as a symptom of another condition are usually relieved when the underlying condition is treated.