Purpose of Review: This article identifies the pertinent historical issues that lead to the identification of those headaches needing additional testing to exclude a serious underlying cause.
Recent Findings: Recurrences of giant cell arteritis, even after presumed successful treatment, are common. Postural orthostatic tachycardia syndrome is an often unrecognized cause of headache.
Summary: Patients with a primary headache disorder are more susceptible to the development of headache when a secondary cause occurs. Their headaches may be phenotypically similar to their primary headache disorder. Therefore, a secondary cause should be considered in patients with preexisting headache disorders who develop a significant increase in the number and severity of those attacks.
Address correspondence to Dr Mark W. Green, Mount Sinai School of Medicine, 5 East 98th St, Floor 7, #1139, New York, NY 10029, firstname.lastname@example.org.
Relationship Disclosure: Dr Green has served as a speaker for Zogenix, Inc., and has performed malpractice reviews.
Unlabeled Use of Products/Investigational Use Disclosure: Dr Green reports no disclosure.