====== Cluster headache ======

Cluster headache (CH) is included under section 3 - Trigeminal autonomic cephalalgias (TAC) of the International Headache Society (IHS) classification. It is one of the most frequent, painful, and disabling primary headaches. 

AKA [[histaminic migraine]]. Actually a neurovascular event, distinct from true [[migraine]]. 

Cluster headache belongs to a group of primary headache disorders, classified as the trigeminal autonomic cephalalgias or (TACs). Cluster headache is named after the demonstrated grouping of headache attacks occurring together (cluster).

[[Cluster headache]]s may also be known as [[histamine headache]], [[red migraine]], [[Horton’s headache]], and cephalalgia or [[sphenopalatine neuralgia]].

===== Epidemiology =====
Male: female ratio is ≈ 5:1. 25% of patients have a personal or family history of migraine.
((Kittrelle JP, Grouse DS, Seybold ME. Cluster Headache: Local Anesthetic Abortive Agents. Arch Neurol. 1985; 42:496–498)).


Cluster headache (CH) is a primary headache disorder classified under Trigeminal Autonomic Cephalalgias (TACs) in the International Classification of Headache Disorders (ICHD), currently in its third edition (ICHD-3). Below is the classification and key features of cluster headache:

===== ICHD-3 Classification of Cluster Headache =====

1. Episodic Cluster Headache

Definition:
Attacks occur in clusters lasting from 7 days to 1 year.
Followed by a remission period of at least 3 months.

2. [[Chronic Cluster Headache]]

Definition:
Attacks occur for more than 1 year without remission or with remission periods shorter than 3 months.