Introduction

While most headaches are episodic in nature, some headaches evolve into a chronic headache syndrome. It is estimated that more than 4% of the adults in the US have chronic daily headache (CDH).⁷⁶ The majority of these persistent daily headaches have mixed features consistent with a migraine component and a tension-type component. Chronic daily headaches are often lumped together under the heading of “transformed migraine.” The latter designation suggests that episodic headache has evolved over time into a chronic syndrome. This phenomenon can sometimes be identified among patients who are frequently using analgesics of any type, or who appear to develop clear rebound from overuse of ergotamine preparations. The pathophysiologic basis for the transformation of episodic headaches into their chronic versions is not understood. In some cases, physical or emotional trauma, major life changes, surgery, and hormonal changes in women may act as catalysts. A detailed discussion of the diagnosis and management of primary headache syndromes can be found in other sources.⁷⁷ The following discussion will briefly review the challenges of treating patients with CDH.