Chronic Daily Headache

Individuals presenting with chronic daily headache (CDH) are considered among the most difficult and labor-intensive patients in a neurologist's practice. However, when treated successfully, they can be the most rewarding. Successful treatment plans can be life-changing for patients. Unfortunately, due to both patient and physician-related factors, many individuals with CDH lapse from medical care and seek alternative therapies, and some continue spiraling downward, fueled by medication misuse and overuse. CDH is not a diagnosis but the presence of headache on at least 15 days/month for at least 3 months. Patients with CDH need secondary etiologies excluded through appropriate investigations before establishing treatment programs. Table 1 lists secondary causes of CDH to which the clinician must be alert. Imaging is frequently necessary to exclude secondary causes, and in the majority of cases, MRI is superior to CT because of causes that are often overlooked or not visible on head CT (table 2). In this article, we review primary CDH and discuss evidence-based treatment strategies. View this table: Table 1 Causes of primary and secondary chronic daily headache View this table: Table 2 Potential etiologies for headache that are often overlooked on head CT ### Short-duration CDH. Determining the usual duration (greater or less than 4 hours) of individual headache episodes will refine the differential diagnosis in patients with primary CDH. The prototypical short-lasting primary CDH (<4 hours) is chronic cluster headache (CCH), a trigeminal autonomic cephalalgia (TAC) characterized by severe orbital or temporal pain with accompanying cranial autonomic features such as nasal congestion or lacrimation. Cluster headache becomes chronic if attacks occur for more than 1 year with remissions lasting less than 1 month. Other TACs that may mimic CCH include chronic paroxysmal hemicrania (CPH), short-lasting unilateral neuralgiform headaches with conjunctival injection and tearing (SUNCT) syndrome, and short-lasting unilateral neuralgiform headaches with autonomic symptoms but without lacrimation and conjunctival injection (SUNA). These differ in …