A cluster headache is often confused with a migraine, but they are distinct neurological disorders. Both are classified as primary headache disorders, meaning the headache itself is the main illness, not a symptom of another condition. They involve complex neurological processes and are recognized as separate entities by the International Headache Society. Understanding the differences in pain profile and patterns is essential for accurate diagnosis and effective management.
Core Distinction: The Pain Profile
The subjective experience of the pain offers the clearest diagnostic separation between the two headache disorders. Cluster headaches are renowned for their excruciating severity, often described as a stabbing, burning, or piercing sensation localized around or behind one eye or temple. Attacks are frequently accompanied by autonomic symptoms on the affected side of the face, including:
- A watery or red eye.
- A blocked or runny nose.
- A drooping eyelid.
- Facial flushing or sweating.
In contrast, a migraine attack is characterized by a throbbing or pulsating pain that is moderate to severe in intensity. While migraine pain is often unilateral, it can be bilateral or shift sides, unlike the fixed location of a cluster headache. Migraines are also associated with systemic symptoms like nausea, vomiting, and a heightened sensitivity to light (photophobia) and sound (phonophobia).
The behavioral responses to the pain also differ significantly between the two conditions. A person experiencing a migraine typically seeks stillness, preferring to lie down quietly in a dark room because movement worsens the pain. Conversely, individuals with a cluster headache are often restless and agitated, unable to sit still, and may pace or rock during the attack.
Timing and Pattern
The temporal characteristics, including the duration and frequency of attacks, further distinguish these two headache types. An individual cluster headache attack is relatively short-lived, lasting anywhere from 15 minutes to three hours. It is possible to experience multiple attacks in a single day, sometimes up to eight times.
The name “cluster headache” refers to the pattern of occurrence, where frequent attacks happen during a specific time frame, known as a cluster period. These periods can last for weeks or months, followed by long periods of remission, sometimes lasting for years. A unique feature is their remarkable regularity, often striking at the same time each day or night, sometimes waking the person from sleep.
Migraine attacks, by comparison, are much longer in duration, typically lasting between four and 72 hours if left untreated. While migraines can be episodic, occurring a few times a month, they generally do not follow the predictable, cyclic pattern seen with cluster periods. It is rare for a person to experience more than one migraine attack per day.
Treatment Approaches
The distinct clinical profiles necessitate different treatment strategies for both acute attacks and long-term prevention. For an acute cluster headache attack, the primary goal is rapid relief due to the explosive onset and intense severity of the pain. High-flow oxygen, administered through a non-rebreather mask, is a highly effective first-line acute treatment. Fast-acting triptans, such as sumatriptan, are also used, and are most effective when administered via injection or nasal spray for quicker onset.
Cluster Prevention
Preventative treatment for cluster headaches often involves medications like the calcium channel blocker verapamil, taken daily to reduce the frequency and severity of attacks. For episodic cluster headaches, the CGRP inhibitor galcanezumab has emerged as a first-line prophylactic treatment.
Migraine Treatment
Acute migraine relief often relies on oral triptans, which are effective because the longer attack duration allows time for absorption. Migraine prevention employs a broader range of medications, including beta-blockers, certain anti-seizure medications, and CGRP inhibitors. Treatments effective for a cluster headache, such as high-flow oxygen, are not typically used for migraine, and vice versa.