Empiric use of oxygen for acute atraumatic, unilateral, retro-orbital headaches.

This article describes a man who presented with a 2-week history of atraumatic, unilateral, retro-orbital cranio-facial pain, ipsilateral diaphoresis, and facial flushing. He was diagnosed with cluster headaches after a positive response to oxygen therapy. Early consideration for oxygen therapy in the acute setting should be considered in all patients with an acute, unilateral, retro-orbital headache.