Cluster headache is a debilitating primary headache disorder with two subtypes — episodic and chronic — that are currently defined according to a temporal cut-off.Cluster headache pathogenesis involves complex interactions between the trigeminovascular pathway, trigeminal autonomic reflex, hypothalamus and the neuropeptides calcitonin gene-related peptide and pituitary adenylate cyclase-activating polypeptide 38.Emerging therapies in cluster headache include calcitonin gene-related peptide monoclonal antibodies, non-invasive vagus nerve stimulation and sphenopalatine ganglion stimulation.Clinical studies of these emerging treatments have highlighted differences between episodic and chronic cluster headache that imply different underlying mechanisms that could be used to distinguish them.
