Margaret is a 25-year-old solicitor who has been married for 5 years, her husband having been her first and only sexual partner. She presents to you as her General Practitioner with a 4-day history of itch in the vulva and a little vaginal discharge. Her general health is good and she has not had similar symptoms before. Her last menstrual period had ended 8 days previously; she uses the combined oral contraceptive pill. She tells you that her husband has had mild itch and redness of his penis, these symptoms developing a few hours after most recent sexual intercourse 2 days previously.