Clinical Features

• Agonizing pain

• Strictly unilateral, periorbital, and/or temporal

• Quickly developing (within minutes), short, recurring attacks that usually occur in a cyclical pattern (“cluster periods”)

  • May become chronic (less common), with interruptions of less than three months between cluster bouts [2]

  • Attacks often wake patients up during sleep.

• Ipsilateral autonomic symptoms

  • Conjunctival injections and/or lacrimation

  • Rhinorrhea and nasal congestion

  • Partial Horner syndrome: ptosis and miosis, but no anhidrosis

• Restlessness and agitation

• Clinical diagnosis

  • Perform a diagnostic workup for headache.

  • Rule out red flag symptoms for headache.

• Consider obtaining an initial MRI head to rule out secondary headaches.

In patients with high-risk headaches, obtain further diagnostics to rule out life-threatening secondary headaches (e.g., SAH, meningitis).