eMedicine Specialties > Emergency Medicine > Neurology

Headache, Cluster

Author: Lori K Sargeant, MD, Consulting Staff, Summa Emergency Associates, Inc
Coauthor(s): Michelle Blanda, MD, Chair, Department of Emergency Medicine, Summa Health System; Professor of Emergency Medicine, Northeastern Ohio Universities College of Medicine
Contributor Information and Disclosures

Updated: Nov 5, 2009

Introduction

Background

Cluster headache, also known as histamine headache, is a form of neurovascular headache. Attacks usually are severe and unilateral and typically are located at the temple and periorbital region. The pain is typically associated with ipsilateral lacrimation, nasal congestion, conjunctival injection, miosis, ptosis, and lid edema. Each headache is brief in duration, typically lasting a few moments to 2 hours. Cluster refers to a grouping of headaches, usually over a period of several weeks. To fulfill criteria for diagnosis, patients must have had at least 5 attacks occurring from 1 every other day to 8 per day and no other cause for the headache.

The 2 existing forms of cluster headache are (1) episodic clusters with at least 2 cluster phases lasting 7 days to 1 year separated by a cluster-free interval of 1 month or longer, and (2) chronic form, in which the clusters occur more than once a year without remission or the cluster-free interval is less than 1 month.

Pathophysiology

The pathophysiology of cluster headaches is not well understood. Some proposed mechanisms are described here.

Hemodynamic: Vascular dilatation may play a role, but blood flow studies are inconsistent. Extracranial blood flow (hyperthermia and increased temporal artery blood flow) increases but following the onset of pain. Vascular change is considered secondary to primary neuronal discharge.

Trigeminal nerve: The trigeminal nerve may be responsible for neuronal discharge causing cluster headaches. Substance P neurons carry sensory and motor impulses in the maxillary and ophthalmic divisions of the nerve. These connect with the sphenopalatine ganglion and interior carotid perivascular sympathetic plexus. Somatostatin inhibits substance P and reduces the duration and intensity of cluster headaches.

Autonomic nervous system: Sympathetic (eg, Horner syndrome, forehead sweating) and parasympathetic (eg, lacrimation, rhinorrhea, nasal congestion) effects occur.

Circadian rhythm: Cluster headaches often recur at the same time every day, suggesting that the hypothalamus, which controls circadian rhythms, may be the site of activation.

Serotonin: This is not as striking as in migraines, but some changes are seen.

Histamine: Although evidence supporting a causative role is inconsistent, cluster headaches may be precipitated with small amounts of histamine. Antihistamines do not abort cluster headaches.

Mast cells: Increased numbers of mast cells have been found in the skin of painful areas of some patients, but this finding is inconsistent.

Frequency

United States

Incidence is estimated to be 2-9% of migraine sufferers, making it relatively uncommon compared with classic migraines. Prevalence in males is 0.4-1%.

International

Incidence in the United Kingdom is equivalent to that of multiple sclerosis.

Mortality/Morbidity

No reported mortality is directly associated with cluster headaches, although suicides have been reported in cases where attacks are frequent and severe. The intensity of the attacks often leads those who experience cluster headaches to miss time from activities such as work or school.

Race

Cluster headaches may be underdiagnosed in black women, but ethnic differences have not been studied.

Sex

This condition is more common in males than in females. The male-to-female ratio was 6:1 in the 1960s but now is 2:1.

Age

Cluster headaches usually begin in middle adult life. The mean age of onset is 30 years for men and later for women.

Clinical

History

No aura exists as in migraines. Periodicity is the most striking characteristic. Typically, a patient experiences 1-2 cluster periods per year, each lasting 2-3 months.

• Pain - Described as lancinating and severe
  • Sudden onset - Peaks in 10-15 minutes
  • Unilateral facial - Remains on the same side during the cluster period
  • Duration - 10 minutes to 3 hours per episode
  • Character - Boring and lancinating, as if eye is being pushed out
  • Distribution - First and second divisions of the trigeminal nerve (Approximately 18-20% of patients complain of pain in the extratrigeminal areas [eg, back of the neck, along carotid artery].)
  • Frequency - May occur several times a day for 1-4 months (often nocturnal)
  • Periodicity - Circadian regularity in 47%
  • Remission - Long symptom-free intervals occur in some patients. The average remission is 2 years but ranges from 2 months to 20 years.
• Lacrimation (84-91%) or conjunctival injection
• Nasal stuffiness (48-75%) or rhinorrhea
• Ipsilateral eyelid edema
• Ipsilateral miosis or ptosis
• Ipsilateral forehead and facial perspiration (26%)
• Restlessness/agitation (90%)

Physical

Physical examination findings should be normal except for the lacrimation and conjunctival injection that may occur. Ptosis can also be seen. Accompanying findings are consistent with ipsilateral autonomic features characterized by cranial parasympathetic activation and sympathetic hypofunction. The presence of other abnormalities suggests another etiology for the headache.

• Parasympathetic overactivity
  • Ipsilateral lacrimation
  • Conjunctival injection
  • Rhinorrhea or congestion
• Ocular sympathetics paralysis - Mild Horner syndrome (eg, ptosis, miosis, anhidrosis)
• Bradycardia
• Facial flushing or pallor
• Scalp and facial tenderness
• Ipsilateral carotid tenderness (in some patients)
• Patient often is in severe distress.
  • Patient may lower the head and press on the site of pain, sometimes crying or screaming.
  • Physical exercise may help some patients obtain relief.
  • Patient may threaten suicide.

Causes

Provocation of cluster headache attacks

• Subcutaneous injection of histamine provokes attacks in 69% of patients.
• Attacks are triggered in some patients by stress, allergens, seasonal changes, or nitroglycerin.
• Alcohol induces attacks during a cluster but not during remission. Of patients with cluster headache, 80% are heavy smokers and 50% have history of heavy ethanol use.
• Risk factors
  • Male sex
  • Older than 30 years
  • Small amounts of vasodilators (eg, alcohol)
  • Previous head trauma or surgery (occasionally)

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