New daily persistent headache (NDPH) is a primary headache syndrome which can mimic chronic migraine and chronic tension-type headache. The headache is daily and unremitting from very soon after onset (within 3 days at most), usually in a person who does not have a history of a primary headache disorder. The pain can be intermittent, but lasts more than 3 months. Headache onset is abrupt and people often remember the date, circumstance and, occasionally, the time of headache onset. One retrospective study stated that over 80% of patients could state the exact date their headache began.The cause of NDPH is unknown, and it may have more than one etiology. NDPH onset is commonly associated with an infection or flu-like illness, stressful life event, minor head trauma, and extra cranial surgery. Infection or flu-like illness and stressful life event are most often cited. The pathophysiology of NDPH is poorly understood. The syndrome is difficult to treat and may persist for years. The age of onset ranges from 6 to greater than 70 years old, with a mean of 35 years. It is found to be more common in females in both the adult and pediatric populations. NDPH is rare. The Akershus study of chronic headache, a population based cross sectional study of 30,000 persons aged 30–44 years in Norway, found a one-year prevalence of 0.03 percent in the population.In 1986, Vanast was the first author to describe the new daily-persistent headache (NDPH) as a benign form of chronic daily headache (CDH).
The criteria for the diagnosis of NDPH were proposed in 1994 (the Silberstein–Lipton criteria)  but not included in the International Classification of Headache Disorders (ICHD) until 2004. Signs and symptoms
The headaches can vary greatly in their clinical presentation and duration.Quality of the headache has been described as dull and/or pressure-like sensation, and throbbing and/or pulsating sensation. The pain is usually on both sides of the head (in 88–93% of people with NDPH), but may be unilateral, and may be localized to any head region. The pain can fluctuate in intensity and duration, is daily, and lasts more than 3 months.There may be accompanying photophobia, phonophobia, lightheadedness or mild nausea. Co-morbidity with mood disorders has been reported in a subset of patients.Cranial autonomic nervous symptoms occur with painful exacerbations in 21%, and cutaneous allodynia may be present in 26%.In 2002, Li and Rozen conducted a study of 56 patients at the Jefferson Headache Center in Philadelphia and published the following results:

82% of patients were able to pinpoint the exact day their headache started. 30% of the patients, the onset of the headache occurred in correlation with an infection or flu-like illness. 38% of the patients had a prior personal history of headache. 29% of the patients had a family history of headache. 68% reported nausea. 66% reported photophobia. 61% reported phonophobia. 55% reported lightheadedness.Imaging and laboratory testing were unremarkable except for an unusually high number of patients who tested positive for a past Epstein-Barr virus infection.