Although tension type headache is present in up to 78% of headache patients in population-based studies, it is the least distinct of all headache types. Its clinical diagnosis is based chiefly on negative features (that is, absence of symptoms that characterize other primary or secondary headaches). For example, the absence of unilaterality, absence of pulsatile and throbbing character, lack of aggravation by physical activity, lack of nausea and vomiting, lack of photo and photophobia etc.
However, it is to be understood that a minority of TTH patients can have some of these features. For example 18% may have pulsatile headache, 10% unilateral pain, 28% aggravation on routine physical activity, 18% anorexia, 4% nausea, and 11% photophobia.[21
] Further, many of the secondary headache types may mimic TTH at some stage of their clinical evolution [the common secondary causes mimicking TTH are listed in the ]. Therefore, as a general dictum, atypical history or abnormal clinical examination in patients of suspected TTH indicate the need for further investigations by computed tomography or magnetic resonance imaging. However, the vast majority with typical history and normal clinical examination will have a very low likelihood of significant intracranial disease and therefore do not need further investigations.
Differential diagnosis of chronic tension type headaches