Diagnosis of Primary Chronic Daily Headaches

Abstract

Chronic daily headache (CDH) is a term of art meaning headaches present at least 15 days/month, at least 4 h/day untreated, present at least 3 months. CDH is generally primary, but many clinicians include Medication Overuse Headache (MOH) in the term. CDH is not a diagnosis in the International Classification of Headache Disorders. The four primary chronic daily headaches are: Chronic Tension-Type Headache (CTTH), Hemicrania Continua (HC), New Daily Persistent Headache (NDPH), and Chronic Migraine (CM). CTTH is a low level, featureless headache, almost never with impact. HC is a unilateral, mild to moderate headache with periodic severe exacerbations, accompanied by autonomic signs. HC is defined by its indomethacin responsiveness. NDPH is probably best diagnosed as abrupt onset primary CDH of any phenotype. Primary CM is a primary CDH in which a patient transforms from episodic migraine to CDH without secondary causes, thereby excluding medication overuse. MOH is not a primary CDH; it is characterized by overuse of enough acute medication to transform a patient to secondary CDH. The FDA defined “chronic migraine” as CDH, both primary and secondary.