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Page last reviewed: July 2013

Page last updated: July 2013

Content source: Centers for Disease Control and Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Division of STD Prevention

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        - Vaginitis

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Vaginal Environment

The vagina is a dynamic ecosystem that normally contains approximately 109 bacterial colony-forming units per gram of vaginal fluid. The normal vaginal discharge is clear to white, odorless, and of high viscosity. The normal bacterial flora is dominated by lactobacilli, but a variety of other organisms, including some potential pathogens, are also present at lower levels. Lactobacilli convert glycogen to lactic acid. Lactic acid helps to maintain a normal acidic vaginal pH of 3.8 to 4.2. Some lactobacilli produce H2O2 (hydrogen peroxide), which kills bacteria and viruses.


Vaginitis is usually characterized by a vaginal discharge, vulvar itching and irritation, and a vaginal odor. The three most common diseases diagnosed among women with these symptoms include bacterial vaginosis (40%- 45%), vulvovaginal candidiasis (20%-25%), and trichomoniasis (15%- 20%). In some cases, the etiology may be mixed, and there may be more than one disease present.

Other causes of vaginal discharge or irritation include the following:

         Normal physiologic variation

         Allergic reactions, e.g., spermicides, deodorants

         Herpes Simplex Virus (HSV)

         Mucopurulent cervicitismay be related to Chlamydia trachomatis or Neisseria gonorrhoeae infection

         Atrophic vaginitisfound in lactating and post-menopausal women and related to a lack of estrogen

         Vulvar vestibulitis, lichen simplex chronicus, and lichen sclerosis (especially pruritis)

         Foreign bodies, e.g., retained tampons

         Desquamative inflammatory vaginitis


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