June 1998

Vaginitis Due to Vaginal Infections

Vaginitis is an inflammation of the vagina characterized by discharge, odor, irritation, and/or itching. The cause of vaginitis may not always be determined adequately solely on the basis of symptoms or a physical examination. For a correct diagnosis, a doctor should perform laboratory tests including microscopic evaluation of vaginal fluid. A variety of effective drugs are available for treating vaginitis.

Vaginitis often is caused by infections, which cause distress and discomfort. Some infections are associated with more serious diseases. The most common vaginal infections are bacterial vaginosis, trichomoniasis, and vaginal yeast infection or candidiasis. Some vaginal infections are transmitted through sexual contact, but others such as yeast infections probably are not, depending on the cause.

Bacterial Vaginosis

Bacterial vaginosis (BV) is the most common cause of vaginitis symptoms among women of childbearing age. Previously called nonspecific vaginitis or Gardnerella-associated vaginitis, BV is associated with sexual activity. BV reflects a change in the vaginal ecosystem. This imbalance, including pH changes, occurs when different types of bacteria outnumber the normal ones. Instead of Lactobacillus bacteria being the most numerous, increased numbers of organisms such as Gardnerella vaginalis, Bacteroides, Mobiluncus, and Mycoplasma hominis are found in the vaginas of women with BV. Investigators are studying the role that each of these microbes may play in causing BV, but they do not yet understand the role of sexual activity in developing BV. A change in sexual partners and douching may increase the risk of acquiring bacterial vaginosis.

Symptoms. The primary symptom of BV is an abnormal, odorous vaginal discharge. The fish-like odor is noticeable especially after intercourse. Nearly half of the women with clinical signs of BV, however, report no symptoms. A physician may observe these signs during a physical examination and may confirm the diagnosis by doing tests of vaginal fluid.

Diagnosis. A healthcare worker can examine a sample of vaginal fluid under a microscope, either stained or in special lighting, to detect the presence of the organisms associated with BV. They can make a diagnosis based on the absence of lactobacilli, the presence of numerous "clue cells" (cells from the vaginal lining that are coated with BV organisms), a fishy odor, and decreased acidity or change in pH of vaginal fluid.

Treatment. All women with BV should be informed of their diagnoses, including the possibility of sexual transmission, and offered treatment. They can be treated with antibiotics such as metronidazole or clindamycin. Generally, male sex partners are not treated. Many women with symptoms of BV do not seek medical treatment, and many asymptomatic women decline treatment.

Complications. Researchers have shown an association between BV and pelvic inflammatory disease (PID), which can cause infertility and tubal (ectopic) pregnancy. BV also can cause adverse outcomes of pregnancy such as premature delivery and low-birth-weight infants. Therefore, the U.S. Centers for Disease Control and Prevention (CDC) recommends that doctors check all pregnant women for BV who previously have delivered a premature baby, whether or not the women have symptoms. If these women have BV, they should be treated with oral metronidazole or oral clindamycin. A pregnant woman who has not delivered a premature baby should be treated if she has symptoms and laboratory evidence of BV. BV is also associated with increased risk of gonorrhea and HIV infection (HIV, human immunodeficiency virus, causes AIDS).

Trichomoniasis

Trichomoniasis, sometimes referred to as "trich," is a common STD that affects 2 to 3 million Americans yearly. It is caused by a single-celled protozoan parasite called Trichomonas vaginalis. Trichomoniasis is primarily an infection of the urogenital tract; the urethra is the most common site of infection in man, and the vagina is the most common site of infection in women.

Symptoms. Trichomoniasis, like many other STDs, often occurs without any symptoms. Men almost never have symptoms. When women have symptoms, they usually appear within four to 20 days of exposure. The symptoms in women include a heavy, yellow-green or gray vaginal discharge, discomfort during intercourse, vaginal odor, and painful urination. Irritation and itching of the female genital area, and on rare occasions, lower abdominal pain also can be present. The symptoms in men, if present, include a thin, whitish discharge from the penis and painful or difficult urination.

Treatment. Because men can transmit the disease to their sex partners even when symptoms are not present, it is preferable to treat both partners to eliminate the parasite. Metronidazole is the drug used to treat people with trichomoniasis. It usually is administered in a single dose. People taking this drug should not drink alcohol because mixing the two substances occasionally can cause severe nausea and vomiting.

Complications. Research has shown a link between trichomoniasis and two serious sequelae. Data suggest that trichomoniasis is associated with increased risk of transmission of HIV and may cause a woman to deliver a low-birth-weight or premature infant. Additional research is needed to fully explore these relationships.

Prevention. Use of male condoms may help prevent the spread of trichomoniasis, although careful studies have never been done that focus on how to prevent this infection.

Vaginal Yeast Infection

Vaginal yeast infection or vulvovaginal candidiasis is a common cause of vaginal irritation. Doctors estimate that approximately 75 percent of all women will experience at least one symptomatic yeast infection during their lifetimes. Yeast are always present in the vagina in small numbers, and symptoms only appear with overgrowth. Several factors are associated with increased symptomatic infection in women, including pregnancy, uncontrolled diabetes mellitus, and the use of oral contraceptives or antibiotics. Other factors that may increase the incidence of yeast infection include using douches, perfumed feminine hygiene sprays, and topical antimicrobial agents, and wearing tight, poorly ventilated clothing and underwear. Whether or not yeast can be transmitted sexually is unknown. Because almost all women have the organism in the vagina, it has been difficult for researchers to study this aspect of the natural history.

Symptoms. The most frequent symptoms of yeast infection in women are itching, burning, and irritation of the vagina. Painful urination and/or intercourse are common. Vaginal discharge is not always present and may be minimal. The thick, whitish-gray discharge is typically described as cottage-cheese-like in nature, although it can vary from watery to thick in consistency. Most male partners of women with yeast infection do not experience any symptoms of the infection. A transient rash and burning sensation of the penis, however, have been reported after intercourse if condoms were not used. These symptoms are usually self-limiting.

Diagnosis. Because few specific signs and symptoms are usually present, this condition cannot be diagnosed by the patient's history and physical examination. The doctor usually diagnoses yeast infection through microscopic examination of vaginal secretions for evidence of yeast forms.

Scientists funded by the National Institute of Allergy and Infectious Diseases (NIAID) have developed a rapid simple test for yeast infection, which will soon be available for use in doctors’ offices. If such a test were available for home screening, it would help them to appropriately use yeast medication.

Treatment. Various antifungal vaginal medications are available to treat yeast infection. Women can buy some antifungal creams, tablets, or suppositories (butoconazole, miconazole, clotrimazole, and tioconazole) over the counter for use in the vagina. But because BV, trichomoniasis, and yeast infection are difficult to distinguish on the basis of symptoms alone, a woman with vaginal symptoms should see her physician for an accurate diagnosis before using these products.

Other products available over the counter contain antihistamines or topical anesthetics that only mask the symptoms and do not treat the underlying problem. Women who have chronic or recurring yeast infections may need to be treated with vaginal creams for extended periods of time. Recently, effective oral medications have become available. Women should work with their physicians to determine possible underlying causes of their chronic yeast infections. HIV-infected women may have severe yeast infections that are often unresponsive to treatment.

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 may include allergic and irritative factors or other STDs. Noninfectious allergic symptoms can be caused by spermicides, vaginal hygiene products, detergents, and fabric softeners. Cervical inflammation from these products often is associated with abnormal vaginal discharge, but can be distinguished from true vaginal infections by appropriate diagnostic tests.

In an effort to control vaginitis, research is under way to determine the factors that promote the growth and disease-causing potential of vaginal microbes. No longer considered merely a benign annoyance, vaginitis is the object of serious investigation as scientists attempt to clarify its role in such conditions as pelvic inflammatory disease and pregnancy-related complications.

NIAID is a component of the National Institutes of Health (NIH), which is an agency of the Department of Health and Human Services. NIAID supports basic and applied research to prevent, diagnose, and treat infectious and immune-mediated illnesses, including HIV/AIDS and other sexually transmitted diseases, illness from potential agents of bioterrorism, tuberculosis, malaria, autoimmune disorders, asthma and allergies.

News releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov.

Prepared by:
Office of Communications and Public Liaison
National Institute of Allergy and Infectious Diseases
National Institutes of Health
Bethesda, MD 20892

Department of Health and Human Services

National Institutes of Health (NIH) Bethesda, Maryland 20892

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