Herpetic encephalitis (Orphanet_1930, an Orphanet rare-disease nomenclature term) can be described as follows. Herpetic encephalopathy (HSE) is caused by Herpes simplex virus (HSV) and affects the frontal and temporal lobes, resulting in personality changes, cognitive impairment, aphasia, seizures, and focal weakness. The disease is potentially fatal. Also known as: HSV encephalitis, Herpes simplex encephalitis, Herpes simplex neuroinvasion.