Cluster headache: focus on emerging therapies.

Cluster headache is a strictly unilateral headache that occurs in association with cranial autonomic features. It is an excruciating syndrome and is probably one of the most painful conditions known to mankind with female patients describing each attack as being worse than childbirth. In most patients, it has a striking circannual and circadian periodicity. This disorder has a highly stereotyped clinical phenotype and responds to specific therapies, thereby underlying the importance of distinguishing it from other primary headache syndromes. In this review, the clinical manifestations, differential diagnosis, diagnostic workup and treatment options for this syndrome have been outlined.