Chronic Migraine

Chronic migraine is a primary headache disorder defined by ≥ 15 headache days per month, of which ≥8 fulfill criteria for migraine, persisting for over three months. Pathophysiology involves hyperexcitability of the trigeminovascular system, cortical spreading depression, and central sensitization. Clinical features include pulsatile headache, photophobia, phonophobia, and nausea. Diagnosis is based on International Classification of Headache Disorders criteria and exclusion of secondary causes. Management involves acute abortive therapy, preventive pharmacotherapy, and lifestyle modifications; prognosis depends on adherence to preventive measures and comorbidity management.