Systemic herpes infections

Herpes simplex virus is a common infection in childhood. Typically infections are asymptomatic or benign vesicular lesions or ulcers of the skin or lips. However, under certain circumstances such as in the newborn period, in occasional normal children, or in the immunocompromised child, systemic disease can occur involving the central nervous system and/or other organs. New knowledge is emerging about the underlying mechanisms that result in systemic HSV diseases in infants and some older children, but not others. Neonatal herpes results from a combination of high inocula of virus and immunological immaturity. HSV encephalitis in older children can be associated with genetic defects in innate immune responses. Characteristic herpetic lesions can be absent on occasions in the newborn and rashes may be atypical in appearance in the immunocompromised, so a high index of suspicion is required. Prompt recognition, diagnosis using rapid assays and molecular techniques to determine the presence of viral DNA in sterile sites, and institution of intravenous antiviral therapy is essential for a good outcome. Encephalitis and disseminated disease in the newborn is still associated with high incidence of adverse neurological outcomes. Future research is needed to improve rapid diagnosis and reduce morbidity in survivors of systemic HSV disease.