As previously discussed, the differential diagnosis of the acute headaches requires a systematic approach. In a 1990 review article, John Edmeads stated that even when a patient is quiet and calm, able and willing to present an orderly history, and easy to examine, the headache diagnosis may be difficult (Edmeads 1990). However, during an attack, headache sufferers may not be completely cooperative, and, consequently, the quality of the information may be affected. We have herein presented an orderly approach to differential diagnosis. The precise criteria for each disorder are presented elsewhere (Headache Classification Committee of the International Headache Society 2004). These algorithms should help neurologists move forward quickly and safely when assessing patients with acute headaches.