Classification of daily and near-daily headaches: proposed revisions to the IHS criteria.

The International Headache Society (IHS) headache classification, while a major advance, does not adequately classify the daily and near-daily headache disorders known as chronic daily headache (CDH). We believe that chronic daily headache is a group of disorders which includes chronic tension-type headache (CTTH), transformed migraine (TM), new daily persistent headache (NDPH), and hemicrania continua (HC). We propose specific criteria for transformed migraine, new daily persistent headache, and hemicrania continua, and have modified the criteria for chronic tension-type headache.