NDPH onset is commonly associated with an infection or flu-like illness, stressful life event, minor head trauma, and extra cranial surgery.
[citation needed] Cranial autonomic nervous symptoms occur with painful exacerbations in 21%, and cutaneous allodynia may be present in 26%.
[6] In 2002, Li and Rozen[1] conducted a study of 56 patients at the Jefferson Headache Center in Philadelphia and published the following results: Imaging and laboratory testing were unremarkable except for an unusually high number of patients who tested positive for a past Epstein-Barr virus infection.
NDPH mimics include but are not limited to:[citation needed] Many doctors state that the condition is best viewed as a syndrome rather than a diagnosis.
[citation needed] NDPH is classified as a Primary Headache Disorder by the ICHD-2 classification system (by the IHS) using number 4.8.
This exclusion due to migrainous features could have adverse scientific, diagnostic, and treatment consequences.
[11] One proposal for reclassification of the criteria is from a study conducted on retrospective analysis of the records of 1348 patients regularly treated at the headache clinic of the Department of Neurology of Santa Casa de São Paulo, Brazil, and would be the following subdivision: NDPH with migraine features and without migraine features that would allow the inclusion of all individuals present who has a daily and persistent headache from the beginning.
The revised criteria for NDPH definition does not exclude migraine features (NDPH-R), and three subdivisions were created and described based on prognosis: Persisting, remitting, and relapsing–remitting.
[13][14] In 1987, Vanast first suggested autoimmune disorder with a persistent viral trigger for CDH (now referred to as NDPH).
A study by Rozen and Swindan in 2007 found elevated levels of tumor necrosis factor alpha, a proinflammatory cytokine, in the cerebrospinal fluid but not the blood of patients with NDPH, chronic migraine, and post-traumatic headaches suggesting inflammation as the cause of the headaches.
[22] A mean 5-year retrospective analysis of 53 patients with a history of viral meningitis and 17 patients with a history of bacterial meningitis showed an increased onset of subsequent new onset headache and increased severity of those with prior primary headaches.
[27] Opiates, or narcotics, tend to be avoided because of their side effects, including the development of medication overuse headaches and potential for dependency.
[2] To avoid the development of medication overuse headaches, it is advised not to use pain relievers for more than nine days a month.
NDPH, like other primary headaches, has been linked to comorbid psychiatric conditions, mainly mood and anxiety and panic disorders.