What do we know about chronic tension-type headache?

In the past few years there has been an increasing body of knowledge about etiological mechanisms of chronic tension type headache (CTTH), permitting a better understanding of this syndrome. It seems that CTTH diagnostic criteria should be modified to improve its differential diagnosis against migraine, since CTTH is a syndrome of "featureless" headaches characterized by nothing but pain in the head. It has been demonstrated that pressure pain hypersensitivity and pericranial muscle tenderness are both consequence and not causative factors of CTTH. An updated pain model has suggested that CTTH can be explained by referred pain from trigger points (TrPs) in the cranio-cervical muscles, mediated through the spinal cord and the trigeminal nerve nucleus caudalis. Different therapeutic strategies (pharmacological and non-pharmacological) are generally used for the management of these patients. CTTH is generally treated with non-steroidal anti-inflammatory drugs (NSAIDs), tricyclic antidepressants, and physical therapy, although the therapeutic efficacy of these approaches is controversial.