Challenging or difficult headache patients.

This article addresses interesting and enigmatic presentations of headache from a diagnostic and treatment perspective. The emphasis is on migraineurs and other headache patients who represent a significant burden for the primary care provider. In particular, the author focuses on undiagnosed migraine, menstrual migraine, migraine in pregnancy, intractable migraine and status migrainosus,transformed migraine, hemiplegic migraine, basilar migraine, "triptan syndrome," sudden onset of severe headache, post-traumatic headache, and headache in elderly patients.