Tension Type Headache.

Tension type headache (TTH) is the most common headache and it has been discussed for years without reaching consensus on its pathophysiology, or proper rationale management. This primary headache remains a challenge into its management for clinicians. This review aims to provide an updated and critical discussion on what is currently known and supported by scientific evidence about TTH and which gaps there still may be in our understanding of this condition. Clinical features of TTH resemble common manifestations of muscle referred pain. Episodic TTH may evolve into the chronic form by different aspects and several triggers may be involved at the same time. Both peripheral and central sensitization mechanisms seem to be clearly involved in this process. Individuals with episodic TTH exhibit higher levels of peripheral excitability whereas chronic TTH clearly show central sensitization manifestations. The role of associated muscle hyperalgesia seems to be important factors in TTH. Therapeutic management of individuals with TTH should be multimodal including appropriate use of pharmacological and non-pharmacological interventions to reduce the nociceptive peripheral drive to the central nervous system. If properly applied, treatment may not only reduce the number of TTH attacks but may also prevent or delay the transition from episodic to chronic TTH. Scientific evidence of pharmacological and nonpharmacological treatment is discussed in this review.