Cluster headache is the most common form of trigeminal autonomic cephalgia, and it affects less than 1% of the population. It is characterized by attacks of severe unilateral pain located in the orbital, supraorbital, and/or temporal region. This article provides a review of patient-oriented evidence to guide the diagnosis and management of cluster headache.

Epidemiology and Risk Factors

• Typical age of onset is 20 to 40 years^1,2; it is two to three times more common in men than women.³

• Lifetime prevalence is 124 per 100,000.⁴

• Having a first-degree relative with cluster headache increases the patient's risk five to 18 times, whereas having a second-degree relative with cluster headache increases the risk one to three times.⁵

Diagnosis

• Cluster headache is a clinical diagnosis based on the criteria described in Table 1.²

• Cluster headache patterns are episodic or chronic. Headache episodes that last seven days to one year with remission periods lasting three months or longer are episodic. When episodes last for one year or longer with remission periods of less than three months, they are categorized as chronic.¹

• A suggested approach to the evaluation of acute headache is summarized in Figure 1.^1,2,6

DIFFERENTIAL DIAGNOSIS

• The differential diagnosis of cluster headache includes other trigeminal autonomic cephalgias such as paroxysmal hemicrania, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing, short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms, hemicrania continua, or secondary cluster headache caused by intracranial structural lesions (e.g., pituitary adenoma).^1,7

• Trigeminal neuralgia typically affects the second and third branches of the trigeminal nerve, whereas the first branch is affected in cluster headache.^1,7

• Migraine headaches are often accompanied by other symptoms that are not typical of cluster headache, including photophobia, phonophobia, and nausea or vomiting. Most patients with migraine find movement worsens their headache, whereas patients with cluster headache can feel agitated and restless.^1,7

HISTORY AND PHYSICAL EXAMINATION

• The typical presentation of cluster headache is unilateral severe pain in the orbital, supraorbital, and/or temporal region and is associated with one or more ipsilateral autonomic symptoms, including conjunctival injection, lacrimation, rhinorrhea, nasal congestion, miosis and/or ptosis, eyelid edema, and facial sweating.^1,7 Another key symptom is a sense of restlessness.^1,3,7

• A cluster headache can last from 15 to 180 minutes when untreated and occurs up to eight times per day in a long-term pattern.¹

• Triggers include medications (vasodilators) such as nitroglycerin, histamine release, tobacco exposure, alcohol, foods that contain nitrates, nail varnish, and petroleum.^1,2

DIAGNOSTIC TESTING

• Neuroimaging with computed tomography or magnetic resonance imaging is not routinely recommended.

• Imaging should be performed in patients with sudden changes in headache features (e.g., sudden onset, frequency, severity, location, worst headache of the patient's life), presence of neurologic findings (e.g., double vision, blindness, weakness, change in mental status or personality), or systemic illness (e.g., fever, rash).^1,2,6