A 12-year-old girl was referred for evaluation of vulvar ulcers. Ten days prior to her visit, she developed a fever lasting for 3 days. On the third day of her fever, she developed dysuria and was seen by her pediatrician, who treated her for a presumed urinary tract infection. Within a few days, however, she developed severe vulvar pain and was seen at a local emergency department where viral cultures of an ulcer for herpes simplex and urine cultures were obtained. Results of both were negative, and she was treated empirically with valacyclovir hydrochloride, prednisone, and trimethoprim/sulfamethoxazole.