Update on Chronic Daily Headache

Chronic daily headache (CDH), defined as a primary headache occurring at least 15 days per month, is a problem of worldwide scope, which is seen in 3% to 5% of the population. Though it has been recognized since ancient times, only recently have there been attempts to define and classify it. CDH usually consists of a mixture of migraine and tension-type headaches (TTH), with the more severe headaches having migraine features and the less severe...