Chronic Daily Headache

Assessment and Diagnosis of CDH

CDH usually refers to chronic tension-type headache (defined by the International Headache Society as headache attacks occurring more frequently than 15 days per month for a period of 6 months),⁸³ with intermittent attacks of migraine. The patient with CDH may experience daily or nearly daily headaches, with each headache episode lasting 4 or more hours.⁸⁴ Typically, the headache history will reveal that the patient has a history of migraine headaches since adolescence or early adulthood, and the headache frequency has increased over time.⁸⁵ Tension-type headaches become interspersed among the migraines until the patient has one or the other type of headache every, or nearly every, day. Chronic daily headaches are often lumped together under the heading of “transformed migraine”, and as a group, are characterized by analgesic overuse and ergotamine rebound.

A focused neurological examination is also important to rule out secondary causes for the headaches.⁸⁶ Neuroimaging procedures or analysis of serum or cerebrospinal fluid are indicated when one of the red flags for secondary headache disorders” is present.

The pathophysiological basis for transformation of episodic migraine or tension-type headache to a chronic form is not clear but, physical or emotional trauma, major life changes, surgery, and hormonal changes in women may act as catalysts.⁸⁶ Many patients with CDH overuse analgesics, including triptans or ergotamine, which may act to perpetuate the daily headache with rebound headaches following their discontinuation. Significant headache-related disability and comorbid conditions such as depression, anxiety, insomnia, and fibromyalgia may also play a role in maintaining the chronic daily headache. Thus, the persistent nature of the headache and frequent comorbid psychiatric or analgesic use problems often render persistent headaches difficult to manage in primary practice.^86,87