Advances in the Treatment of Cluster Headache

Cluster headache (CH) is one of the trigeminal autonomic cephalalgias (TACs), which are primary headache disorders characterised by unilateral head pain occurring in association with prominent ipsilateral cranial autonomic features, such as lacrimation, conjunctival injection or nasal symptoms.1,2 TACs include paroxysmal hemicrania (PH) and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) or short-lasting unilateral neuralgiform headaches with cranial autonomic symptoms (SUNA). Whether hemicrania continua (HC) should be included is moot.3 Currently, TACs are grouped into section three of the revised International Classification of Headache Disorders (ICHD-III).4 TACs differ in attack duration and frequency, as well as response to therapy: CH has the longest attack duration and relatively low attack frequency; PH has intermediate duration and intermediate attack frequency; SUNCT has the shortest attack duration and the highest attack frequency; and HC is marked by continuous pain with exacerbations, which can include cranial autonomic symptoms as part of the phenotype. In this article, recent advances in CH will be set against the importance of first making the diagnosis and the distinction from other TACs, and then in terms of recent developments in therapy.