Localized herpes simplex (HSV) type II following intra-articular corticosteroid injection is remarkable. We describe a 51-year-old woman with sacroiliitis following a fall. She was treated with an intra-articular injection of 80 mg methylprednisolone into her sacroiliac joint, followed 2 days later by a cluster of herpetiform vesicles adjacent to the injection site. Swab of punctured vesicles demonstrated HSV type II by polymerase chain reaction. One plausible explanation is HSV reactivation secondary to localized immunosuppression from corticosteroid injection.