G44.0: Cluster headache

You get repeated severe headaches.

The headaches usually occur at night and only on one side of your head. The headaches occur in bouts, and often last for several minutes or a few hours. The headaches are usually particularly severe around the eye and the temple. The eye or face may also turn red. The eye may water and the nose may run.

The cause of this type of headache is unknown. The headaches may occur more frequently when alcohol is drunk.

Additional indicator

On medical documents, the ICD code is often appended by letters that indicate the diagnostic certainty or the affected side of the body.

  • G: Confirmed diagnosis
  • V: Tentative diagnosis
  • Z: Condition after
  • A: Excluded diagnosis
  • L: Left
  • R: Right
  • B: Both sides

Further information


This information is not intended for self-diagnosis and does not replace professional medical advice from a doctor. If you find an ICD code on a personal medical document, please also note the additional indicator used for diagnostic confidence.
Your doctor will assist you with any health-related questions and explain the ICD diagnosis code to you in a direct consultation if necessary.


Provided by the non-profit organization “Was hab’ ich?” gemeinnützige GmbH on behalf of the Federal Ministry of Health (BMG).