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IHS Diagnosis ICD-10
3.1.2 Chronic cluster headache G44.02  


Cluster headache attacks occurring for more than 1 year without remission or with remissions lasting less than 1 month.

Diagnostic criteria:

  1. Attacks fulfilling criteria A-E for 3.1 Cluster headache
  2. Attacks recur over >1 year without remission periods or with remission periods lasting <1 month


Chronic cluster headache may arise de novo (previously referred to as primary chronic cluster headache) or evolve from the episodic subtype (previously referred to as secondary chronic cluster headache). Some patients may switch from chronic to episodic cluster headache.