Data regarding the location of a headache is informative. Migraine headache is unilateral in two-thirds of attacks and is commonly associated with nausea, vomiting, and sensitivity to light, sound, and smells. Inflammation of an extracranial artery from temporal arteritis causes pain localized to the site of the vessel. Lesions of the paranasal sinuses, teeth, eyes, and upper cervical vertebrae induce a less sharply localized pain but still one that is referred to a certain region, usually the forehead or maxilla or around the eyes. Intracranial lesions in the posterior fossa generally cause pain in the occipitonuchal region and usually are homolateral if the lesion is one-sided. Supratentorial lesions induce frontotemporal pain, or approximate the site of the lesion. Localization, however, may also be deceiving. Pain in the frontal regions may be caused by such diverse lesions and mechanisms as glaucoma, sinusitis, thrombosis of the vertebral or basilar artery, pressure on the tentorium, and increased intracranial pressure. Similarly, ear pain may signify disease of the ear itself, but as often, it is referred from other regions, such as the throat, cervical muscles, spine, or structures in the posterior fossa. Periorbital and supraorbital pain, while usually indicative of local disease, may reflect dissection of the cervical portion of the internal carotid artery. Headaches localized to the vertex or biparietal regions are infrequent and should raise the suspicion of sphenoid or ethmoid sinus disease or thrombosis of the superior sagittal venous sinus.
The mode of onset, the variation of the pain over time, and duration of the headache, with respect both to a single attack and to the profile of the headache over a period of years, are also useful data. At one extreme, the headache of subarachnoid hemorrhage (caused by a ruptured aneurysm) occurs as an abrupt attack that attains its maximal severity in a matter of seconds or minutes, or, in the case of meningitis, it may come on more gradually, over several hours or days. Simulating the rapid onset, severe headache of subarachnoid hemorrhage are a group of “thunderclap headaches” of diverse causes but principally cerebral venous thrombosis and vasospasm syndromes. Brief sharp pain, lasting a few seconds, in the eyeball (ophthalmodynia) or cranium (“ice-pick” pain) and “ice-cream headache” caused by pharyngeal cooling is more common in migraineurs and are significant only by reason of their benignity.