[Cluster headache].

Cluster headache is characterized by recurrent unilateral attacks of headache of great intensity and brief duration (15-180 minutes), accompanied by local signs and symptoms of autonomic dysfunction including conjunctival injection, lacrimation, nasal congestion, rhinnorrhea, forehead and facial sweating, miosis, ptosis or eyelid edema. Attacks occur in so-called cluster periods lasting for weeks or months. About 10% of patients have chronic symptoms with no period of remission. There are only two abortive treatments with proven efficacy: subcutaneous sumatriptan and nasal oxygen inhalation. Prophylactic treatment is often needed to reduce the daily frequency of attacks: verapamil in episodic cluster headache and lithium in chronic cluster headache.