The main symptom of a cluster headache is a steady, sharp burning pain affecting one side of the head. The pain often involves one side of the face (from the neck to the temples) and frequently occurs in or around an eye or in the temple. The neck pain and facial pain may radiate to the forehead, nose, cheek or upper gum on the affected side.

Cluster headaches typically develop suddenly, often two to three hours after the patient falls asleep. The pain rapidly intensifies, typically peaking within five to 10 minutes after appearing. Peak pain may last anywhere from 30 minutes to two hours.

Cluster headaches may be accompanied by a number of other symptoms, including:

• Swelling below or around the eyes and eye pain, typically the eye on the affected side of the head
  
  
• Extreme tearing from the eye on the affected side of the head
  
  
• Redness of the eye on the affected side of the head
  
  
• Decreased pupil size
  
  
• Drooping eyelid
  
  
• Restlessness
  
  
• Red, flushed face
  
  
• Excessive sweating
  
  
• Runny nose or nasal congestion, typically affecting the nostril on the affected side of the head

In most cases, the signs and symptoms that accompany cluster headaches vanish once the head pain disappears. Decreased pupil size and drooping eyelid (Horner’s syndrome), however, can persist. In addition, a number of symptoms associated with migraines (e.g., nausea, sensitivity to light and sound, aura) can also occur with cluster headaches.