Cluster headache: a review.

Cluster headache is a rare headache entity that predominantly occurs in younger males. The clinical features are characterized by sudden attacks of unilateral excruciating pain localized periorbitally, associated with ipsilateral autonomic symptoms. The attacks occur in periods: clusters. The pathophysiology is still unknown. Such vasodilating substances as histamine, nitroglycerin and alcohol may provoke attacks. These substances may be used as diagnostic tests, but the interpretation of a negative result must be careful, as the attacks can not be induced in a refractory period after spontaneous occurrence, or at the beginning and end of cluster periods. As symptomatic treatment, ergotamine is the drug of first choice. High attack frequency may lead to overconsumption with ergotisme and further increased frequency. In such cases and for nocturnal attacks, oxygen inhalations represent an alternative. As prophylactic treatment ergotamine, methysergide, lithium and prednisone have proved efficacious. Most patients benefit from such treatment and may become virtually free from attacks. It is, therefore, important to differentiate this headache entity from classical migraine, common migraine and trigeminal neuralgia.