Revised 2004 International Classification of Headache Disorders: new headache types

In 1988, the International Headache Society created a classification system that has become the standard for headache diagnosis and research. The International Classification of Headache Disorders galvanized the headache community and stimulated nosologic, epidemiologic, pathophysiologic, and genetic research. It also facilitated multinational clinical drug trials that have led to the basis of current treatment guidelines. While there have been criticisms, the classification received widespread support by headache societies around the globe. Fifteen years later, the International Headache Society released the revised and expanded International Classification of Headache Disorders second edition. The unprecedented and rapid advances in the field of headache led to the inclusion of many new primary and secondary headache disorders in the revised classification. Using illustrative cases, this review highlights 10 important new headache types that have been added to the second edition. It is important for neurologists to familiarize themselves with the diagnostic criteria for the frequently encountered primary headache disorders and to be able to access the classification (www.i-h-s.org) for the less commonly encountered or diagnostically challenging presentations of headache and facial pain.