Vaginitis is defined as a spectrum of conditions that cause vaginal and sometimes vulvar symptoms, such as itching, burning, irritation, odor, and vaginal discharge. Vulvovaginal complaints are one of the most common reasons for women to seek medical advice.

Etiology and Diagnosis of Vaginitis

The most common infectious causes of vaginitis are bacterial vaginosis, vulvovaginal candidiasis, and trichomoniasis. Physicians traditionally diagnose vaginitis using the combination of symptoms, physical examination, pH of vaginal fluid, microscopy, and the whiff test. When combined, these tests have a sensitivity and specificity of 81 and 70 percent, respectively, for bacterial vaginosis; 84 and 85 percent for vulvovaginal candidiasis; and 85 and 100 percent for trichomoniasis when compared with the DNA probe standard.¹ Table 1 describes common causes, symptoms, and signs of vaginitis,^2,3 and Table 2 lists risk factors that contribute to the development of the condition.^3–11

In a review of studies published between 1966 and 2003, bacterial vaginosis was diagnosed in 22 to 50 percent of symptomatic women, vulvovaginal candidiasis in 17 to 39 percent, and trichomoniasis in 4 to 35 percent. Approximately 30 percent of symptomatic women remained undiagnosed after clinical evaluation.² Among multiple individual symptoms and signs, only the following were found to be helpful for the diagnosis of vaginitis in symptomatic women:

• A lack of itching makes diagnosis of vulvovaginal candidiasis unlikely (range of likelihood ratios [LRs], 0.18 [95% confidence interval (CI), 0.05 to 0.70] to 0.79 [95% CI, 0.72 to 0.87]).

• A lack of perceived odor makes bacterial vaginosis unlikely (LR, 0.07 [95% CI, 0.01 to 0.51]).

• Presence of inflammatory signs is more commonly associated with vulvovaginal candidiasis (range of LRs, 2.1 [95% CI, 1.5 to 2.8] to 8.4 [95% CI, 2.3 to 3.1]).

• Presence of a fishy odor on examination is predictive of bacterial vaginosis (LR, 3.2 [95% CI, 2.1 to 4.7]).

• Lack of odor is associated with vulvovaginal candidiasis (LR, 2.9 [95% CI, 2.4 to 5.0]).²

Individual symptoms and signs, pH level, and microscopy results often do not lead to an accurate diagnosis of vaginitis. Laboratory tests perform better than standard office-based evaluation for diagnosing causes of vaginitis,² but they do not add substantially to the treatment threshold and are justified only in patients with recurrent or difficult-to-diagnose symptoms. Table 3 describes laboratory tests used to diagnose infectious causes of vaginitis.^2,12–24

A cost-effectiveness analysis of diagnostic strategies for vaginitis undiagnosed by pelvic examination, wet-mount preparation, and related office tests showed that the least expensive strategy was to perform yeast culture, gonorrhea and chlamydia probes at the initial visit, and Gram stain and Trichomonas culture only when the vaginal pH exceeded 4.9. Other strategies cost more and increased duration of symptoms by up to 1.3 days.²⁵

Bacterial Vaginosis

Bacterial vaginosis is the most prevalent cause of vaginal discharge or malodor, occurring in up to 30 percent of women.²⁶ It occurs when the normal Lactobacillus species in the vagina are replaced with anaerobic bacteria, resulting in reduced levels of hydrogen peroxide and organic acids usually present in the vagina.

The underlying cause of bacterial vaginosis is not fully understood. More than 50 percent of women with bacterial vaginosis are asymptomatic. The fishy odor caused by production of amines from anaerobic bacteria found in many of these patients is predictive of bacterial vaginosis.² When vaginal alkalinity increases after sexual intercourse (with the presence of semen) and during menses (with the presence of blood), the odor becomes more prevalent.²⁷ Vaginal discharge is a more common but less specific symptom. Bacterial vaginosis is not associated with vaginal mucosal inflammation and rarely causes vulvar itch.²⁷

Bacterial vaginosis, even when asymptomatic, is associated with a high incidence of endometritis and pelvic inflammatory disease following abortion and gynecologic procedures in the general population. Among women with bacterial vaginosis, no overall increased risk of developing pelvic inflammatory disease has been found.²⁸ Bacterial vaginosis is associated with late miscarriages, premature rupture of membranes, and preterm birth.²⁹ Both symptomatic and asymptomatic bacterial vaginosis have been strongly linked with an increased risk of human immunodeficiency virus (HIV)-1 transmission (relative risk, 1.89; 95% CI, 1.46 to 2.43).³⁰

DIAGNOSIS

In clinical practice, bacterial vaginosis is diagnosed by the presence of three out of four Amsel criteria³¹:

• Thin, homogenous vaginal discharge

• Vaginal pH greater than 4.5

• Positive whiff test (fishy amine odor when 10 percent potassium hydroxide solution is added)

• At least 20 percent clue cells (vaginal epithelial cells with borders obscured by adherent coccobacilli on wet-mount preparation or Gram stain; Figure 1).

In a prospective observational study of 269 women, a vaginal pH of more than 4.5 was found to be the most sensitive (89 percent) and a positive whiff test was the most specific (93 percent) method of detecting bacterial vaginosis.¹² The positive presence of these two tests is as sensitive as three or more Amsel criteria.¹² Culture of Gardnerella vaginalis is not recommended because of low specificity. Cervical cytology has no clinical value for diagnosing bacterial vaginosis, especially in asymptomatic women, because it has low sensitivity.¹³

TREATMENT IN NONPREGNANT WOMEN

Current treatment recommendations from the Centers for Disease Control and Prevention (CDC) are listed in Table 4.^13,32 Nonpregnant women with symptomatic disease require antibacterial therapy to relieve vaginal symptoms. Other benefits of treatment include decreasing the risk of HIV and other sexually transmitted infections and reducing infectious complications following abortion or hysterectomy.¹³

A Cochrane review of 24 randomized controlled trials (RCTs) showed that clindamycin and metronidazole (Flagyl) are equally effective, achieving clinical cure in 91 and 92 percent of cases, respectively, after two to three weeks of treatment.³³ Six RCTs showed topical and oral antibiotic preparations to be equally effective. One disadvantage of oral regimens is a longer duration of treatment.³³ Intravaginal clindamycin cream is preferred in case of allergy or intolerance to metronidazole. Metronidazole in a single 2-g dose has the lowest effectiveness for treating bacterial vaginosis and is no longer recommended. Metronidazole, 500 mg twice daily for one week, is effective for treating bacterial vaginosis and trichomoniasis.

Although lactobacillus probiotics are safe, there is no conclusive evidence that they are superior to or enhance the effectiveness of antibiotics in the treatment of bacterial vaginosis or prevent its recurrence.³⁴ Treatment of sex partners and follow-up visits if symptoms are resolved are not recommended.

BACTERIAL VAGINOSIS IN PREGNANCY

Bacterial vaginosis is present in up to 20 percent of women during pregnancy. The effect of treating bacterial vaginosis in symptomatic or asymptomatic pregnant women on subsequent preterm delivery has produced conflicting results in clinical trials.^13,35 The U.S. Preventive Services Task Force (USPSTF) recommends against routine bacterial vaginosis screening of asymptomatic pregnant women at low risk of preterm delivery (USPSTF grade D recommendation).³⁶

RECURRENT BACTERIAL VAGINOSIS

Most relapses of bacterial vaginosis occur within the first year and strongly correlate with new sex partners. Reported recurrence rates are 15 to 30 percent within three months.^37,38 One RCT on persistent bacterial vaginosis indicated that metronidazole gel 0.75% (Metrogel), used twice weekly for six months after initial treatment, effectively maintained a clinical cure for six months.³⁹

Trichomoniasis

Symptoms and signs of trichomoniasis are not specific, and diagnosis by microscopy is more reliable. Features suggestive of trichomoniasis are trichomonads seen with saline, leukocytes more numerous than epithelial cells, positive whiff test, and vaginal pH greater than 5.4.² The wet-mount preparation is an inexpensive and quick test with variable sensitivity of 58 to 82 percent,⁴⁰ and is influenced by the experience of the examiner and the number of parasites in the vaginal fluid sample (Figure 2; a video of motile trichomonads is available at http://www.youtube.com/watch?v=DKJnDz6yBSs&feature=fvsr). Adding examination of the spun urine specimen can increase the detection rate of Trichomonas vaginalis from 73 to 85 percent.⁴¹

Treatment should not be based on a Papanicolaou (Pap) smear finding of trichomonads. Newer point-of-care tests (Table 3^2,12–24 ) are more accurate but costly. In one study, the sensitivities of wet-mount preparation, microbiologic culture, rapid antigen testing, and nucleic acid amplification testing were 51, 75, 82, and 98 percent, respectively. Specificity was close to 100 percent for each method.⁴² Polymerase chain reaction analysis of samples from tampons and introital specimens is more accurate than vaginal or cervical swabs and Pap smears, and may be preferable for patient comfort.⁴³

TREATMENT

Almost any nitroimidazole drug given orally in a single dose or over a longer period results in parasitologic cure in 90 percent of cases.⁴⁴ A single 2-g dose of metronidazole is adequate but can cause dyspepsia and metallic taste; compliant patients may prefer a longer regimen at a lower daily dosage with fewer adverse effects. Metronidazole in a dosage of 500 mg twice daily for seven days will treat bacterial vaginosis and trichomoniasis. Metronidazole in a dosage of 2 to 4 g daily for seven to 14 days is recommended for metronidazole-resistant strains.

The parasitologic cure rate of intravaginal nitroimidazole creams is an unacceptably low 50 percent. In RCTs, combined oral and intravaginal treatments have been more effective than oral treatment alone. Sex partners should be treated simultaneously.⁴⁴ To reduce recurrence, partners should avoid resuming sexual intercourse until both have completed treatment and are asymptomatic. Test of cure is not required.¹³

TRICHOMONIASIS IN PREGNANCY

A Cochrane review found that metronidazole is effective against trichomoniasis when taken by women and their partners during pregnancy. A trial of women treated before 23 weeks of gestation was stopped early because women taking metronidazole were more likely to give birth preterm and have low-birth-weight infants.⁴⁵ The CDC (Table 4^13,32 ) recommends giving 2 g of metronidazole as a single dose, preferably after 37 weeks of gestation, and counseling patients about the potential risks and benefits of treatment.

Vulvovaginal Candidiasis

An estimated 75 percent of women will have at least one episode of vulvovaginal candidiasis, and 40 to 45 percent will have two or more.⁴⁶ Changes in the host vaginal environment precipitate and induce pathologic effects of the organism.¹⁴ Several risk factors for vulvovaginal candidiasis are listed in Table 2.^3–11

DIAGNOSIS

Although symptoms of vulvovaginal candidiasis such as pruritus, vaginal soreness, dyspareunia, and vaginal discharge are common, none of them are specific.² Most patients can be diagnosed by microscopic examination (Figure 3) of vaginal secretions with a 10% potassium hydroxide solution (sensitivity, 65 to 85 percent). Vaginal pH is usually normal (4.0 to 4.5). Vaginal culture should be considered in recurrently symptomatic women with negative microscopy and a normal pH. The Pap smear, although specific, is insensitive, with positive results in only about 25 percent of patients with culture-positive symptomatic vulvovaginal candidiasis.¹⁴ A rapid yeast detection test (Savyon Diagnostics) can be performed by the patient and costs less than $10, compared with a mean of $65 for the yeast culture.¹⁵ Polymerase chain reaction testing is considered the most sensitive method, but is very expensive.

TREATMENT

On the basis of clinical presentation, microbiology, host factors, and response to therapy, vulvovaginal candidiasis can be classified as uncomplicated or complicated.¹³ Patients with uncomplicated vulvovaginal candidiasis are not pregnant, are otherwise healthy, and have all of the following:

• Mild to moderate disease

• Fewer than four episodes of candidiasis per year

• Pseudohyphae or hyphae visible on microscopy.

Treatment of uncomplicated vulvovaginal candidiasis involves a short course of antifungals⁴⁷ (Table 4^13,32 ); oral and topical preparations are similarly effective.^13,48

Patients with complicated vulvovaginal candidiasis have one or more of the following:

• Moderate to severe disease

• Four or more episodes of candidiasis per year

• Only budding yeast visible on microscopy

• Adverse host factors (e.g., pregnancy, diabetes mellitus, immunocompromise).

Treatment of complicated vulvovaginal candidiasis involves an intensive, longer course of antifungals (Table 4^13,32 ).

Noninfectious Causes of Vaginitis

Irritant contact dermatitis and allergic contact dermatitis are two noninfectious causes of vaginitis. They may be associated with use of feminine hygiene products or contraceptive materials, among many other causes. Atrophic vaginitis can manifest clinically with symptoms of vaginal dryness, itching, discharge, irritation, and dyspareunia. It affects 10 to 40 percent of women who have conditions associated with estrogen deficiency.⁴ Diagnosis is based on history and physical findings, supplemented by vaginal pH levels, vaginal wet-mount preparation (to exclude superimposed infection), and, rarely, culture or cytology. Both systemic and topical estrogen treatments are effective in relieving symptoms. Topical vaginal estrogen is preferred because of the low systemic absorption and reduced risk of adverse effects compared with oral therapy. Estrogen-containing creams, pessaries, intravaginal tablets, and the estradiol vaginal ring appear equally effective for the symptoms of atrophic vaginitis.⁴⁹

Data Sources: We reviewed recent relevant publications in the Cochrane Database, InfoPOEMS, and the National Guideline Clearing-house, and searched Pub Med for vaginitis topics. The search included meta-analyses, randomized controlled trials, clinical reviews, and clinical trials. Terms included vaginitis, trichomoniasis, bacterial vaginosis, candidal vulvovaginitis, and atrophic vaginitis. Search date: March 2010.