Hallmarks of primary headache: part 3 – cluster headache

Abstract Background: Cluster headache (CH) is a rare primary headache disorder characterized by recurrent episodes of strictly unilateral excruciating pain accompanied by trigemino-autonomic signs, which significantly impacts the quality of life, social interactions, and occupational functioning of those who are affected. To promote a better understanding of this disabling condition and to foster research on the topic, this review provides a comprehensive description of the hallmarks of CH, including its clinical presentation, diagnostic challenges, pathophysiology, and current and novel therapeutic