A 5-year-old hyperkinetic but otherwise healthy child presented with recurrent irritable vesicles and erosions of the anterior chest wall; they have been apparent since the age of 15 months. Wound swab cultures yielded herpes simplex virus type-2 (HSV-2) and Western blot serology showed past exposure to both HSV-1 and HSV-2. Skin biopsy results further supported a herpes virus infection. Magnetic resonance imaging of the brain showed right temporal lobe atrophy. An evaluation showed no evidence of sexual abuse in the patient but a Western blot assay of the mother's serum for HSV-2 was positive, while the father's was negative. In view of the diagnosis of HSV-2 infection in such a young patient, the possible routes of transmission and the time of acquisition of infection were explored. We believe the most likely route of infection in this child was postnatal, through intimate contact with the mother.