Herpes zoster occurs seldom in infants, especially in the absence of exposure to maternal varicella either intrauterine or postnatal. We report on a case in a 3-month-old infant admitted for herpes zoster in the sciatic nerve territory. No cutaneous eruption was found in the mother or in people who were in contact with the patient. This rare clinical situation is here reviewed, showing that the absence of antenatal or postnatal exposure to herpes viruses does not preclude the occurrence of herpes zoster infection in early infancy.