Viruses that have been implicated include Epstein-Barr virus, herpes simplex virus and cytomegalovirus.Non-specific upper respiratory infections including rhinitis and pharyngitis are most often cited by patients. In one study, 46.5% patients recalled a specific trigger with a respiratory tract illness being the most common. In children, almost half report headache onset during an infection. 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.NDPH as an inflammatory, post-infectious manifestation indicates a potential meningoencephalitis event in NDPH patients. Tissue specificity is a general feature of post-infectious, immune-mediated conditions, and the meninges are a type of connective tissue membrane. Inflammation of the meninges was first proposed as a possible pathophysiology for migraine in the 1960s and has recently been explored again. This hypothesis is based on meningeal mast cell activation. Reactive arthritis (ReA) is a post-infectious disease entity of synovium/joints with connective tissue membrane (synovial membrane of the joints) which provides a corollary. NDPH has been reported in Hashimotos encephalopathy, an immune-mediated type of encephalitis. 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. Treatment
There is no specific treatment for NDPH.
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.