[An overview of the revised international classification of headache disorders (ICHD -II)]

The International Headache Society (IHS) revised The International Classification of Headache published in 1988. Old version has facilitated epidemiological and multinational clinical trials. Fifteen years after its original publication, a revised International Classification of Headache Disorders 2nd Edition(ICHD-II) has been unveiled in 2004. Modifications are small but significant. A lot of knowledge and evidences were added to the new version. A revised classification classifies headaches in 14 groups and categorized headache groups into four parts; part 1: primary headache, part 2: secondary headache, part 3: neuralgias and facial pain, and appendix. Physicians should continue to consult the IHS criteria to ensure accurate diagnosis and management for headache.