The migraine attack can be divided into four phases. Premonitory phenomena occur hours to days before headache onset and consist of psychological, neurological, or general symptoms. The migraine aura is comprised of focal neurological phenomena that precede or accompany an attack. Visual and sensory auras are the most common. The migraine headache is typically unilateral, throbbing, and aggravated by routine physical activity. Cutaneous allodynia develops during untreated migraine in 60% to 75% of cases. Migraine attacks can be accompanied by other associated symptoms, including nausea and vomiting, gastroparesis, diarrhea, photophobia, phonophobia, osmophobia, lightheadedness and vertigo, and constitutional, mood, and mental changes. Differential diagnoses include cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoenphalopathy (CADASIL), pseudomigraine with lymphocytic pleocytosis, ophthalmoplegic migraine, Tolosa-Hunt syndrome, mitochondrial disorders, encephalitis, ornithine transcarbamylase deficiency, and benign idiopathic thunderclap headache.