Exanthem Subitum-Associated Encephalitis: Nationwide Survey in Japan

Tetsushi Yoshikawa, Masahiro Ohashi, Fumi Miyake, Ayano Fujita, Chie Usui, Ken Sugata, Sadao Suga, Shuji Hashimoto, Yoshizo Asano

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60 Citations (Scopus)


We sought to clarify clinical features of exanthem subitum associated-encephalitis/encephalopathy, generally caused by primary human herpesvirus-6 infection in Japan. A two-part questionnaire was sent to hospitals between January 2003-December 2004. Of 3357 questionnaires, 2357 (70.2%) were returned, and 2293 (68.3%) were eligible for analysis. Eighty-six cases of exanthem subitum-associated encephalitis/encephalopathy were reported. Seventy-seven (89.5%) of 86 patients were diagnosed with human herpesvirus-6 infection by virologic examination. Although 41 (50.6%) of 81 patients had no sequelae, 38 (46.9%) had neurologic sequelae. Moreover, two fatal cases (2.5%) were reported. Pleocytosis was evident in only 4 (7.5%) of 53 patients, and cerebrospinal fluid protein levels were within normal range (23.4 ± 14.6 mg/dL S.D.) in all patients. Human herpesvirus-6 DNA was detected in 21 (53.8%) of 39 patients. Abnormal computed tomography findings were a predictor of neurologic sequelae (P = 0.0097). As a consequence of this survey, we estimate that 61.9 cases of exanthem subitum-associated encephalitis occur every year. The disease prognosis was unexpectedly poor.

Original languageEnglish
Pages (from-to)353-358
Number of pages6
JournalPediatric Neurology
Issue number5
Publication statusPublished - 11-2009

All Science Journal Classification (ASJC) codes

  • Pediatrics, Perinatology, and Child Health
  • Neurology
  • Developmental Neuroscience
  • Clinical Neurology


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