Cluster headaches.

Cluster headaches are episodes of excruciating unilateral facial pain, typically occurring in young men. Ipsilateral autonomic symptoms of nasal congestion, rhinorrhea, conjunctival injection and lacrimation are commonly present. Characteristic facial features may be found. Migraine and trigeminal neuralgia are two important considerations in the differential diagnosis. Prednisone and lithium are effective prophylactic medications for episodic and chronic forms of cluster headaches. Treatment with oxygen or ergotamines may be useful in aborting attacks.