Complete Resolution of New Daily Persistent Headache With Migraine-Like Features Following Erenumab Treatment: A Case Report

New daily persistent headache (NDPH) is a rare and difficult-to-treat primary headache disorder characterized by a sudden onset of continuous, unremitting pain. We report the case of a 46-year-old Japanese woman with a history of episodic migraine who developed a persistent daily headache with migraine-like features. Despite multiple conventional preventive treatments, her symptoms remained unchanged. Remarkably, she achieved complete and sustained remission after initiating monthly subcutaneous injections of erenumab at a dose of 70 mg. The treatment was maintained for 24 months, during which no recurrence of the continuous headache occurred. This case highlights the diagnostic overlap between NDPH and chronic migraine presenting with continuous daily headache and suggests the potential benefit of calcitonin gene-related peptide-targeted therapy in patients with migraine-like NDPH phenotypes. Careful phenotypic characterization may improve therapeutic decision-making and support a syndromic approach to managing continuous daily headache disorders.