Acute retinal necrosis caused by herpes simplex virus type 2 in a 3-year-old Japanese boy

Acute retinal necrosis (ARN), which is characterized by rapidly progressing peripheral retinal necrosis, is caused mainly by herpes simplex virus type 1, herpes simplex virus type 2 (HSV-2), or varicella-zoster virus. A previously healthy 3-year-old Japanese boy developed ARN in his left eye after being bruised by a milk container. HSV-2 DNA was detected in the aqueous humor of the affected eye. Serological testing suggested that the route of infection was from mother to child, although there was no past history of apparent HSV-2 infection. Childhood ARN has not been previously reported in Japan, possibly because of the low seroprevalence of HSV-2 in Japanese women. Pediatricians must be aware of this rare disease, which can affect individuals without a previous history of HSV even in a country with a low seroprevalence of HSV-2.