14-year-old girl with insulin-dependent diabetes mellitus presented to us with a 3-day history of burning vaginal pain. She had no fever, vomiting, or diarrhea. She had no previous hospital admissions for diabetes, and had no history of any sexually transmitted diseases. Examination showed an erythematous and edematous perineal area dotted with numerous painful vesicles extending over the entire external genital organs, including clitoris, labia majora and the anal region (Fig. 1); along with inguinal lymphadenopathy. There was no vaginal discharge. Blood gas analysis revealed metabolic acidosis, and urine examination confirmed presence of glycosuria and ketonuria. We diagnosed her as having diabetic ketoacidosis induced by　genital herpes　infection. Herpetic serology was initially negative, but seroconversion for herpes simplex virus 2 (IgM) was documented after one month. She was treated with intravenous aciclovir (10 mg/kg/dose 8 hourly) for 10 days along with insulin therapy. Genital lesions began to improve after two days of treatment.

Fig. 1 Multiple vesicles over genital region in an adolescent girl.