Abstract 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 her- pes simplex virus infection in 42% and cytomegalovirus in 11% of cases; moreover we could not find any EBV infec- tion. Our data suggest that viruses other than EBV can play a role in NDPH. Key words New daily persistent headache • Clinical characteristics • Laboratory tests • Viral infection New daily persistent headache (NDPH) was first described by Vanast [1] in 1986 and was included by Silberstein et al. [2] in 1994 in his classification of chronic headaches. The II edition of the IHS classification of headache disorders [3] included NDPH in its fourth chapter. Beside the prima- ry subtype, secondary NDPH has been described [4]. Only two retrospective series have been published until now [1, 5]; little is known about clinical aspects of NDPH. A link with viral (in particular Epstein-Barr virus (EBV)) infec- tions has been postulated [6, 7]. By means of a computerised database, we retrospec- tively analysed 2232 new headaches diagnosed from June 1998 to March 2004 in our headache centre. NDPH were diagnosed according to the II edition of IHS classification [3] and, before its publication, following the Silberstein criteria [2]. Two hundred and sixty-five (11.8%) were “chronic headache”: 96 of them (36.5%) chronic tension-type headache, 149 (56.6%) transformed migraine, 18 (6.7%) NDPH and 2 (0.7%) hemicrania continua. Among 18 NDPH, 11 were females and 7 males. Mean age of onset was 23 years (ranging from 15 to 76 years) in females and 39 in males (ranging from 13 to 62 years). Peak age of onset was the third decade in females and the fourth decade in males. All patients were able to recall the period of onset of headache with an error margin less than 7 days. Mean period between onset of symptoms and first consul- tation was 126 days. We observed a family history of headache in 33% of cases and another 33% had a previous headache (migraine-like). The onset of NDPH was related to flu-like symptoms in 2 cases and to abdominal surgery in 2 other. Pain, always bilateral, was diffuse in 50% of cases, occipito-nuchal in 22%, frontal in 17% and referred to the vertex in 11%. The intensity of pain was mild in 5 cases and moderate in 13. Headache was described as dull in all cases, but 61% of patients experienced periods of throbbing pain. Fourteen patients described “migrainous” accompanying symptoms: nausea (50% of them), photo- Neurol Sci (2004) 25:S281–S282 DOI 10.1007/s10072-004-0310-8 P. Meineri • E. Torre • E. Rota • E. Grasso New daily persistent headache: clinical and serological characteristics in a retrospective study P. Meineri () • E. Torre • E. Rota • E. Grasso Department of Neurology ASO “S. Croce e Carle” Via Coppino 26, I-12100 Cuneo, Italy e-mail: pieromeineri@hotmail.com