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micrograph of epithelial cells

Micrograph of two epithelial cells, a normal cell, and an epithelial cell covered by bacteria giving the cell a roughened, stippled appearance known as a “clue cell.” Clue cells are a sign of bacterial vaginosis.
Credit: CDC/M. Rein


Vaginitis is an inflammation of the vagina. It is often caused by infections, some of which are associated with serious diseases. The most common vaginal infections are

Some vaginal infections are transmitted through sexual contact, but others, such as yeast infections, probably are not.

Other Causes of Vaginitis

Although most vaginal infections in women are due to bacterial vaginosis, trichomoniasis, or yeast, there may be other causes as well. These causes include other sexually transmitted diseases, allergic reactions, and irritations.

Allergic symptoms can be caused by spermicides, vaginal hygiene products, detergents, and fabric softeners. Inflammation of the cervix (opening to the womb) also is associated with abnormal vaginal discharge. Healthcare providers can tell them apart from true vaginal infections by doing lab tests.


To control vaginitis, research is under way to determine the factors that promote the growth and disease-causing potential of vaginal microbes (germs). This information could help improve efforts to treat and prevent vaginitis. Vaginitis is the object of serious studies as scientists try to clarify its role in such conditions as pelvic inflammatory disease and pregnancy-related complications.

Vaginitis refers to disorders of the vagina caused by infection, inflammation, or changes in the normal vaginal flora. Symptoms include vaginal discharge, odor, itching, and/or discomfort. The three most common diseases diagnosed among women with these symptoms include bacterial vaginosis (40–45 percent), vulvovaginal candidiasis (2025 percent), and trichomoniasis (1520 percent). In some cases, there may be more than one disease present. Recurrent vaginitis is also common.

Research is under way to determine the factors that promote the growth and disease-causing potential of vaginal microbes and their role in vaginitis. These microbes include the sexually transmitted pathogen Trichomonas vaginalis, Candida species, and microbes associated with bacterial vaginosis, such as Gardnerella vaginalis.

NIAID-supported research has led to advances in knowledge about the normal microflora of the vagina, reproductive behavior of yeast, and the genetic code of T. vaginalis. For example, researchers have discovered an association between certain lactobacilli species in the normal microflora in the vagina and protection from bacterial vaginosis (BV). They are investigating a lactobacillus vaginal suppository aimed to help these beneficial bacteria grow in the vagina. Researchers also are studying the use of combination treatment with vaginal lactobacilli suppositories and oral medication to treat BV and prevent its recurrence.

Other NIAID-funded researchers have sequenced the genome of T. vaginalis. Understanding the genome of this pathogen will help researchers understand how it evolves, spreads, and causes disease. T. vaginalis is particularly interesting to medical researchers because it increases both transmission and acquisition of HIV among women. Additionally, both T. vaginalis​ and BV are associated with adverse pregnancy outcomes including preterm birth and low birth weight. Knowledge gained from ongoing research could help improve efforts to treat and prevent vaginitis and also prevent its potential complications.

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Last Updated September 25, 2015