Causes of Vaginal Infections

Three types of infectious organisms account for more than 90% of all vaginal infections: bacteria (bacterial vaginosis), yeast (candida vaginitis) and parasites (trichomonas vaginitis).4

  • Bacterial vaginosis (BV) – Bacterial vaginosis refers to a vaginal infection caused by multiple different types of bacteria (called mixed flora). In healthy women, the primary bacteria colonizing (living in) the vagina are lactobacillus; these bacteria produce lactic acid, which helps to maintain an acidic (low pH) environment. In the setting of bacterial vaginosis, the number of healthy lactobacillus bacteria decreases significantly, and other forms of harmful bacteria colonize the vagina.
  • Candida vaginitis – Candida vaginitis is caused by a widespread airborne fungus. There are a number of different species of candida, but Candida albicans causes more than 90% of fungal vaginitis.3  Candida is part of the normal vaginal flora in some women, but is present in relatively small numbers. When the normal low pH (acidic) environment of the vagina is disturbed, there is a rapid increase in number of candida fungi, and symptoms of a yeast infection develop.
  • Trichomonas vaginitis – Trichomonas vaginitis is caused by a unicellular (single-cell) organism called Trichomonas vaginalis. Unlike the other forms of vaginitis, trichomonas is a sexually transmitted disease, contracted from the male partner during intercourse. There are approximately 5 million new cases of trichomonas diagnosed annually in the US.3

Noninfectious vaginitis can mimic some of the symptoms of infectious vaginitis. Atrophic vaginitis is a condition linked to low estrogen levels in postmenopausal women; thinning of the vaginal walls and vaginal dryness results in vaginal irritation and burning.

Allergic vaginitis refers to vaginal burning and itching related to the presence of irritants and allergens in products including soaps, perfumes and latex.