Migraine 2nd most common cause of headache, Affects 15% of women and 6% of men over a one year period. Usually an episodic headache and associated with ceain features such as sensitivity to light, sound, or movement; nausea and vomiting often accompany the headache. May be associated with other symptoms of neurologic dysfunction in varying admixtures Migraine-prone patients do not habituate easily to sensory stimuli, which is amplified in females during the menstrual cycle. Various triggers, including glare, bright lights, sounds, or other afferent stimulation; hunger; excess stress; physical exeion; stormy weather or barometric pressure changes; hormonal fluctuations during menses; lack of or excess sleep; and alcohol or other chemical stimulation. Ref - Harrisons internal medicine 20e pg 3096