Infection Detection
If itching is due to a vaginal infection, it is most likely a case of bacterial vaginosis, a yeast infection or trichomoniasis. Health care providers, such as gynecologists and midwives, say that the best way to distinguish between these infections is not by looking at symptoms, but by testing the vaginal fluid.
Bacterial Vaginosis
The most common vaginal infection is bacterial vaginosis (BV), which occurs when the balance of the microorganisms that normally live in the vagina is thrown off. BV appears to be related to sexual activity, though doctors aren't sure how. Douching also raises risk.
In BV, there is an overgrowth of certain bacteria, such as Gardnerella vaginalis, that leads to low numbers of a protective bacteria called lactobacilli, causing grayish-white vaginal discharge, itching and a fishy odor. When a gynecologist examines the vaginal fluid under a microscope, he or she will be able to see cells coated with BV bacteria. The doctor will also measure the pH of the vagina, which reflects its acidity. In BV, the vaginal pH is higher than normal. Finally, the health care provider should perform a whiff test, where drops of an alkalinizing fluid are added to the vaginal fluid, to see if it produces a fishy odor.
BV is treated with antibiotics. Untreated BV is associated with pelvic inflammatory disease, a condition that can lead to infertility, tubal pregnancy or premature delivery.