Cluster headache


Cluster headaches are among the most excruciating forms of headaches, often occurring in cyclical patterns called cluster periods. Typically, these headaches awaken individuals during the night, causing severe pain around one eye on a specific side of the head. These cluster periods involve frequent attacks lasting for weeks to months, followed by periods of relief when the headaches subside. These remission phases can extend across several months or even years. 

Healthcare providers classify both types of headaches as primary headaches rather than secondary headaches. The distinction is as follows: 

  • Primary headaches: They start when the part of the brain that deals with pain becomes active. A primary headache is its own health issue and isn’t connected to a bigger problem. 
  • Secondary headaches: They begin due to another health problem. Many things can cause these headaches, like ear infections, stuffy noses, and not having enough water in your body. 

Fortunately, cluster headaches are rare and not lifethreatening. Effective treatments are available to alleviate the intensity and duration of cluster headache episodes. Medications are also prescribed to reduce the frequency of cluster headaches. 


Rapid and often unexpected, a cluster headache might be preceded by migrainelike nausea and aura. Typical signs and symptoms experienced during such a headache include: 

  • Intense, onesided pain around the eye. 
  • Restlessness. 
  • Excessive tearing. 
  • Redness in the affected eye. 
  • Stuffy or runny nose on the same side. 
  • Facial sweating. 
  • Pale or flushed skin on the face. 
  • Swelling around the eye. 
  • Drooping eyelid on the affected side. 

Cluster periods typically last for weeks to months, with consistent timing and duration. They can be seasonal, like every spring or fall. Most individuals experience episodic cluster headaches lasting a week to a year, followed by a painfree period of 3 months or more before the next headache. 

Chronic clusters can persist for over a year, with painfree periods under a month. During a cluster period: 

  • Daily headaches, often multiple times 
  • Attacks last 15 minutes to 3 hours 
  • Regular timing, mostly at night, 1 to 2 hours after sleep 
  • Pain ends suddenly, leaving exhaustion. 

Immediate medical attention is necessary if you experience any of these indications: 

  • Suddenly intense headache, often described as a thunderclap 
  • Headache accompanied by fever, nausea, vomiting, a stiff neck, confusion, seizures, numbness, or difficulty speaking; these could indicate various issues like stroke, meningitis, encephalitis, or a brain tumor 
  • Headache following a head injury, even minor ones, particularly if it gets worse 
  • Rapid onset of an extremely severe headache that differs from your usual headaches 
  • Headache that worsens gradually over several days and changes its usual pattern 


The exact cause of cluster headaches remains elusive, but their pattern suggests involvement of abnormalities in the body’s biological clock, centered in the hypothalamus. Unlike migraines and tension headaches, cluster headaches are not commonly associated with triggers such as dietary elements, hormonal shifts, or stress. However, alcohol consumption can rapidly trigger severe headaches once a cluster period begins, leading many with cluster headaches to avoid alcohol during these episodes. Other potential triggers encompass the use of medications like nitroglycerin, typically prescribed for heart disease. 

Risk factors 

Several risk factors may affect ones susceptibility to getting cluster headaches, such as:  

  • Family history: The risk of cluster headache is higher when a family member has experienced one.  
  • Sex: Previously, researchers believed that these headaches were more common among men. They now believe they have an equal impact on men and women.  
  • Age: While the condition can strike at any age, it commonly affects people between the ages of 20 and 50. Symptoms typically appear at these ages.  
  • Tobacco use: People who smoke are more prone to getting cluster headaches.  
  • Alcohol use: Consuming alcohol during a cluster period may increase the likelihood of having an attack.