Cluster headache and migraine are regarded as distinct primary headaches. While cluster headache and migraine differ in multiple aspects such as gender-related and headache specific features (e.g.,... Show moreCluster headache and migraine are regarded as distinct primary headaches. While cluster headache and migraine differ in multiple aspects such as gender-related and headache specific features (e.g., attack duration and frequency), both show clinical similarities in trigger factors (e.g., alcohol) and treatment response (e.g., triptans). Here, we review the similarities and differences in anatomy and pathophysiology that underlie cluster headache and migraine, discuss whether cluster headache and migraine should indeed be considered as two distinct primary headaches, and propose recommendations for future studies. Show less