Case study: type-specific HSV serology and the correct diagnosis of first-episode genital herpes during pregnancy

It is now known that the physical presentation of genital herpes simplex (HSV) infection can be misleading in making the diagnosis of genital herpes. An incorrect diagnosis can be particularly damaging in pregnancy where it may result in extended exposure of the fetus to antiviral agents, an inappropriate route and timing of delivery and a significant increase in fetal exposure to HSV during labour and delivery. Case 1 describes a 32-year-old woman at 30 weeks in her first pregnancy who had the appearance and clinical course typically ascribed to primary genital HSV infection. In contrast, Case 2, a 24-year-old woman at 34 weeks' gestation, had the physical appearance of a recurrent episode. Type-specific serological testing revealed that what Case 1 was actually experiencing was the first symptomatic reactivation of genital herpes, whereas Case 2 had a true primary genital HSV-2 infection that was accompanied by minimal symptoms. Had serology testing not been available, Case 1 would probably have delivered unnecessarily by Caesarean section, and Case 2 would have been managed as a recurrent infection and allowed to deliver vaginally with potentially disastrous results. These cases illustrate the usefulness of a type-specific serology in diagnosing genital herpes in pregnant women.