Diagnosis of Cluster Headaches

Differential Diagnosis of Cluster Headaches

There are several medical conditions that may cause symptoms similar to cluster headache that must be considered before the diagnosis is determined. Since one of the diagnostic signs of cluster headache is the duration of each attack, if a headache continues for more than 4 hours, the diagnosis of cluster headache should be reconsidered.

Conditions which need to be ruled out before reaching a diagnosis of cluster headaches include:

• Migraine headache - headache is less severe, lasts 4 to 72 hours, is associated with more nausea and vomiting than cluster and patients want to remain completely still during an attack. Other differences in symptoms of migraine headache that are not associated with cluster headache include:

  • presence of an aura (a symptom of classic migraine headache in which the patient sees flashing lights or zigzag lines, or may temporarily lose vision) before or during a headache
  • sensitivity to light (photophobia)
  • response to certain medications (e.g., propranolol) which are not effective for cluster headache
  • absence (usually) of autonomic symptoms (e.g., pallor, sweating, nasal congestion or running nose) although up to 50% of migraine patients may experience some autonomic symptoms
  • may start on one side of the head and then spread over a larger area
  • pain tends to switch sides of the head in successive episodes

• Carotid artery dissection - can cause a one-sided headache with an eyelid that droops but typically occurs in the setting of neck injury. After the headache develops stroke-like spells often follow.

• Chronic and episodic paroxysmal hemicrania - these headaches feel exactly like a cluster headache but are shorter in duration (2 to 45 minutes), occur more frequently (up to 1 per hour, sometimes more than 20 headaches in one day) and affect women more than men. These headaches respond to a drug called indomethacin which is minimally effective, if at all, for cluster headache.
• Short-lasting Unilateral Neuralgiform Pain with Conjunctival Injection and Tearing (SUNCT) - this is a one-sided headache of very brief pain episodes (pain only lasts 30 seconds to 4 minutes) and can occur up to 30 times per hour.
• Hemicrania Continua - this is a one-sided headache that is always present at low-intensity and is associated with pain exacerbation periods (lasting hours to days) in which patients may have autonomic symptoms (eyelid droop, tearing, etc). This headache also responds to indomethacin.
• Hypnic headache - this is like a cluster headache in that headaches awaken a patient from sleep. Unlike cluster, these headaches only occur at night, are less painful than cluster, have less autonomic symptoms, and usually occur in the elderly.
• Trigeminal neuralgia - these are short lasting (seconds to two minutes) stabs of electric-like pain, typically in the face and cheek area and are triggered by factors not associated with cluster (e.g., chewing or anything brushing against the face). These headaches are much shorter in duration, and are not periodic like cluster headache. Trigeminal neuralgia responds to certain medications (e.g., carbamazepine and gabapentin) that are not effective for cluster headaches.

• Symptomatic cluster headaches - these headaches are rare and are thought to be caused by anatomical lesions (e.g., impacted molar teeth, arteriovenous malformations, and metastatic lung cancer). Markers that differentiate symptomatic cluster headache from true cluster headache include:

  • presence of a low-grade headache that does not subside between headache attacks
  • incomplete response to medication
  • headaches do not occur at regular periodic cycles
  • presence of neurologic signs other than the typical miosis and ptosis