Tension-Type Headache: Epidemiology, Diagnosis, and Pathophysiology

Tension-type headache (TTH) is a significant but underappreciated condition that is much more frequent than migraine, 42% versus 11%, and produces significant socioeconomic burden. Why then do research advances in this condition seem to lag? One reason is that precise epidemiologic data are lacking, with lifetime prevalence estimates varying from about 13 to 78%. Also, classification is confounded by whether or not to include the occasional but universal headache as TTH. Furthermore, TTH pathophysiology is debated, with some feeling that the pathophysiology of TTH is similar to and on a spectrum with migraine, and some feeling that it is entirely separate and related to peripheral and muscular mechanisms. More recently, central pain mechanisms have also been implicated in the pathophysiology. In addition, a large body of information connects stress and TTH. Although TTH varies widely in frequency and severity among and within patients, TTH pain, compared with pain in other headache types, could be characterized generally as more mild in severity and more generalized in location. This review discusses the current epidemiologic data and diagnostic challenges in TTH and the current pathophysiologic mechanisms.