Vaginitis - Bacterial Vaginosis, Vulvovaginal Candidiasis, and Trichomoniasis

Vaginitis is an inflammation or infection of the vagina and is among the most common reasons that women visit a healthcare provider.  Common nonspecific symptoms of vaginitis include abnormal, malodorous vaginal discharge, vaginal irritation (burning, itching), dysuria, and dyspareunia.  The most common causes of vaginitis include bacterial vaginosis, vulvovaginal candidiasis (yeast infection), and trichomoniasis, which can occur as coinfections. Vaginitis may also result from diseases such as gonorrhea and chlamydia or other noninfectious causes such as feminine hygiene products, perfumed soap, or spermicidal products. 

Bacterial vaginosis (BV) is the most common cause of vaginitis and is characterized by a shift in the vaginal microbiota.   Vaginitis can also be caused by yeasts such as Candida. Risk factors such as antibiotic use, estrogen therapy, or pregnancy can be responsible for Candida overgrowth. Trichomoniasis is a sexually transmitted infection (STI) caused by the parasite Trichomonas vaginalis. Trichomoniasis causes cervicitis, vaginitis, and urethritis in women, and urethritis (mostly asymptomatic) in men. 

Misdiagnosis of vaginitis can lead to inappropriate treatment or prolongation of symptoms that increase the risk of developing serious complications, such as pelvic floor inflammatory disease or adverse pregnancy outcomes.  Because of the potentially serious complications of vaginitis, proper diagnosis is important. Physical examination findings and office-based or laboratory test results should be used in conjunction with clinical history to determine the diagnosis. 

Quick Answers for Clinicians

What are the symptoms most commonly associated with bacterial vaginosis, vulvovaginal candidiasis, and trichomoniasis?

Bacterial vaginosis (BV), vulvovaginal candidiasis, and trichomoniasis often have nonspecific symptoms, such as a change in vaginal discharge, pruritus, pain, burning, irritation, erythema, dyspareunia, and dysuria. In some cases, symptoms may be indicative of the causative organism, and laboratory testing and treatment decisions should be guided by clinical judgment. Some characteristic signs and symptoms indicative of BV are thin, off-white vaginal discharge, a fishy vaginal odor, and the presence of clue cells (these signs and symptoms are included in a set of clinical criteria for BV diagnosis called the Amsel criteria). At least half of women with BV are asymptomatic. Vulvovaginal candidiasis symptoms are generally nonspecific but may include a thick, white “cottage cheese-like” discharge, with vaginal pruritus. Trichomoniasis is associated with profuse, malodorous, yellow-green frothy discharge with a strawberry cervix. In addition to vaginitis, trichomoniasis may also cause cervicitis and urethritis.

What additional factors should be considered for patients with vaginitis?

Once a patient has been diagnosed with bacterial vaginosis (BV), vulvovaginal candidiasis (yeast infection), and/or trichomoniasis, additional testing or medical management may be indicated. For example, people with BV or trichomoniasis are at increased risk for contracting or spreading sexually transmitted infections (STIs), such as HIV, gonorrhea, and herpes simplex virus (HSV). Furthermore, BV may increase the risk of complications after gynecologic surgery as well as complications of pregnancy, and BV recurrence is common. 

Are bacterial vaginosis or vulvovaginal candidiasis considered sexually transmitted infections?

Bacterial vaginosis (BV) is a common cause of abnormal discharge and vaginitis and results from an overgrowth of anaerobic bacteria and a decrease in normal lactobacilli. It is important to note that BV itself is not a sexually transmitted infection (STI).  By definition, an STI is caused by a source that is not endogenous to the vaginal flora. Because BV results from an overgrowth of normal vaginal bacteria, it does not meet the definition of an STI. However, BV is associated with risk factors such as changes in sexual activity, particularly in individuals with new or multiple sex partners (male or female).

Vulvovaginal candidiasis is also not considered an STI because it is not contagious and is not spread from person to person through sexual contact. However, sexual contact may lead to vulvovaginal candidiasis by causing overgrowth of vaginal flora.

What are the benefits of nucleic acid amplification testing methods for the diagnosis of vaginitis?

Nucleic acid amplification testing (NAAT) has several benefits over other methods such as microscopy, culture, and probe-based assays. One benefit is that NAAT has increased sensitivity compared to more traditional methods. Because of this increased sensitivity, the CDC recommends NAAT over probe-based assays for the diagnosis of trichomoniasis.  In the case of bacterial vaginosis, NAAT is specific and useful in determining the ratio of Lactobacilli (“good” bacteria) to several bacterial vaginosis-associated (“bad”) bacteria. 

In the investigation of potential vulvovaginal candidiasis, NAAT can be used to detect multiple species of Candida simultaneously and can identify species of Candida glabrata that may be resistant to current azole therapies. Additionally, NAAT can detect multiple targets simultaneously and help in diagnosing coinfections using one patient sample.

What special testing considerations are appropriate in cases of complicated or severe vulvovaginal candidiasis?

Vaginal candidiasis that recurs, is resistant to treatment, or presents severely may require vaginal culture to confirm clinical diagnosis or identify unusual species such as Candida glabrata. Azole resistance is becoming more common; susceptibility testing is generally not warranted but may be useful in certain circumstances. 

Indications for Testing

Laboratory testing for the diagnosis of vaginitis is appropriate in women experiencing one or more of the following nonspecific symptoms:

  • A change in vaginal discharge (amount, color, odor)
  • Pruritus
  • Pain
  • Burning
  • Irritation
  • Erythema
  • Dyspareunia
  • Dysuria

Signs and symptoms that may indicate BV-specific testing include thin, off-white vaginal discharge, a fishy vaginal odor, and presence of clue cells (signs and symptoms included in BV diagnostic criteria referred to as the Amsel criteria).

Vulvovaginal candidiasis symptoms are generally nonspecific but may include a thick, white “cottage cheese-like” discharge, with vaginal pruritus.

Trichomoniasis is associated with profuse, malodorous, yellow-green frothy discharge with a strawberry cervix. In addition to vaginitis, trichomoniasis may also cause cervicitis and urethritis.

Laboratory Testing

Screening for vaginitis includes clinical assessment (ie, applying the Amsel criteria of pH, vaginal discharge, clue cells, and “whiff test”) and laboratory diagnosis (Gram stain, fungal culture, and nucleic acid probe and amplification assays). Diagnosis of vaginitis is made using a combination of symptoms, physical examination, and office- or laboratory-based testing. 


Screening tests are performed on vaginal secretions obtained during a routine pelvic examination in a primary care setting.

Recommended Screening Based on Vaginitis Type and Patient Population
Vaginitis Type Population Screening Recommendation
BV Women There are no screening recommendations for asymptomatic women
Pregnant individuals Despite the elevated risk of preterm delivery in pregnant individuals, the CDC and USPSTF recommend against screening for BV in asymptomatic pregnant individuals who are not at increased risk for preterm delivery
Vulvovaginal candidiasis Women There are no screening recommendations for asymptomatic women
Trichomoniasis Women Screening is not recommended for asymptomatic women but may be considered in women receiving care in high-prevalence settings or at high risk for STIsa
Persons with HIV The CDC recommends routine screening of asymptomatic persons with HIV infection for T. vaginalis

aFor example, those with multiple sex partners or history of exchanging sex for payment, illicit drug use, or history of an STI.

USPSTF, U.S. Preventive Services Task Force

Source: USPSTF, 2020 ; CDC, 2021 


Accurate diagnosis is important to determine appropriate treatment and medical management of vaginitis. Recent increasing evidence shows that nucleic acid amplification testing (NAAT) better facilitates accurate detection of vaginitis compared with traditional methods (eg, culture or DNA probes) because it is highly sensitive and can be used to detect multiple targets simultaneously on a single patient specimen. NAAT can be used for the diagnosis of vaginitis due to BV, vulvovaginal candidiasis, and trichomoniasis. Gram stain and culture may be useful in certain situations. Determination of a laboratory testing strategy should be informed by clinical assessment. For example, panel testing may be useful in patients with general symptoms, whereas organism-specific testing may be more useful in patients with characteristic symptoms.

ARUP Laboratory Tests

Panel Testing

Aids in the diagnosis of bacterial vaginosis, vulvovaginal candidiasis, and trichomoniasis

Specific Testing

Aids in the diagnosis of bacterial vaginosis by detection of Lactobacillus (L. gasseri, L. crispatus, and L. jensenii), Gardnerella vaginalis, and Atopobium vaginae

Aids in the diagnosis of vulvovaginal candidiasis and trichomoniasis by detection of Trichomonas vaginalis, Candida glabrata, and other Candida species (C. albicans, C. parapsilosis, C. dubliniensis, and C. tropicalis)

Use to detect T. vaginalis in various specimens


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