Chronic daily headache.

Chronic daily headache (CDH) represents one of the most challenging medical conditions that a health care provider is called on to treat. This article outlines the scope of this misunderstood condition,updates the reader on the revised diagnostic criteria for chronic daily headache, and gives practical insight into diagnosis and treatment. Four specific subtypes of CDH are covered: chronic tension-type headache, chronic migraine, new daily persistent headache, and hemicrania continua. Through better recognition and treatment of this all too common condition, this segment of our population can be better helped to lead quality lives.