Cluster headaches are characterized by attacks of strictly unilateral severe pain which is orbital, supraorbital, temporal or in any combination of these sites associated with one or more of the following, ipsilateral conjunctival injection, lacrimation, nasal congestion, rhinorrhea, forehead and facial sweating, miosis, ptosis, and eyelid edema. Most patients are usually unable to lie down, restless or agitated during an attack. The attacks last 15-180 minutes and occur from once every other day to 8 times a day. Cluster periods usually last for weeks or months separated by remission periods, however about 10-15% of patients have chronic symptoms without remission. Age at onset is usually 20-40 years and prevalence is 3-4 times higher in men than in women. Acute attacks involve activation of the posterior hypothalamic gray matter. Pharmacological treatment for cluster headache can be abortive, prophylactic, or a combination of both methods.