The actual incidence of tension-type headache is not known. Mild and intermittent varieties of tension-type headache is very frequent and most of the sufferers do not seek medical care. This is thought to be the most common form of headache. Chronic variety of tension-type headache can be disabling and require long term treatment. This occurs at least as frequently as migraine headache.
Exact pathogenesis is unknown.
It is believed that there is an alteration of central nociceptive system which leads to the development of this type of headache. However peripheral mechanisms in the scalp muscles may play a role in generating the symptoms. Some of the recent neurophysiological studies reveal abnormalities in the polysynaptic brainstem pathways but it is not clear how exactly this leads to the development of tension-type headache. Emotional and psychological problems are assumed to play a significant role in its pathogenesis. Recurrent episodes of headache lasting minutes to days.