New daily persistent headache: clinical and serological characteristics in a retrospective study.

We present a retrospective clinical study of 18 cases of new daily persistent headache (NDPH), a rare chronic headache, included in the fourth chapter of the II IHS classification; the pathophysiology of NDPH is unknown but a link with viral infections (especially Epstein-Barr virus (EBV)) has been suggested. Comparing our series with the other two published until now, we did not find any particular difference, as regards to clinical aspects. However, our laboratory tests show a recent herpes simplex virus infection in 42% and cytomegalovirus in 11% of cases; moreover we could not find any EBV infection. Our data suggest that viruses other than EBV can play a role in NDPH.