Tension-type headache.

Tension-type headache (TTH) is the most prevalent of all headaches and also represents one of the most expensive clinical conditions for the health system. Despite the high impact of this disorder and the existence of well-established diagnostic criteria, knowledge about TTH is still quite limited. In most cases in which crises are quite sporadic, the patients call this normal headache. However, there is a group of patients with the chronic subtype of this headache whose quality of life is greatly compromised. According to the second edition of the International Classification of Headache Disorders, TTH is a bilateral headache of the tight band of pressure type of mild-to-moderate intensity that does not worsen with routine physical activities and whose associated symptoms are less intense than those observed in migraine. Its physiopathology still awaits better elucidation but the existence of central and peripheral mechanisms is already recognized. From a therapeutic viewpoint, simple analgesics are used for the acute treatment of the condition, and tricyclic antidepressants are the most effective class of drugs for its prevention. Follow-up of these patients over the years has demonstrated that the course of TTH is quite favorable in most cases.