Chronic Daily Headache

Chronic daily headache is defined as headache occurring ≥ 15 days per month for at least three months, encompassing primary disorders (e.g., chronic migraine, tension-type headache) and secondary causes. Etiology includes overuse of analgesics, vascular dysregulation, and central sensitization. Clinical features include persistent or recurrent headache, often with associated nausea, photophobia, or cognitive dysfunction. Diagnosis relies on headache history, examination, and exclusion of secondary causes via neuroimaging or laboratory testing. Management involves behavioral therapy, pharmacologic prophylaxis, treatment of underlying causes, and patient education; prognosis depends on adherence to therapy and identification of triggers.