STI-associated syndromes guide: Vaginitis

On this page:

• Public health importance
• Common STI-associated etiology
• Clinical manifestations
• Diagnostic testing
• Empiric treatment and management
• Follow-up
• Reporting and partner notification
• References

Public health importance

In primary care settings, vaginal discharge is among the most common reasons for gynecological consultation. Bacterial vaginosis (BV), vulvovaginal candidiasis (VVC) and trichomoniasis are the most common infectious causes of vaginal discharge.

Trichomoniasis is sexually transmitted. It is associated with an increased risk of human immunodeficiency virus (HIV) acquisition and transmission^{Footnote 1Footnote 2Footnote 3}. Trichomoniasis in pregnancy may be associated with premature rupture of the membranes, preterm birth and low birth weight^{Footnote 4Footnote 5}.

BV is the most common cause of vaginal discharge in people of reproductive age and is characterized by an overgrowth of genital tract organisms (e.g., Gardnerella vaginalis, Prevotella, Mobiluncus spp.) and a depletion of lactobacilli. BV is not sexually transmitted, however, it is associated with increased acquisition of HIV, human papilloma virus (HPV) and Chlamydia trachomatis (CT)^{Footnote 6Footnote 7}.

VVC is not considered to be sexually transmitted. Approximately 75% of women will experience at least one episode of VVC during their lifetimes and 5%-10% will have more than one episode. Persistent Candida colonization and an increased incidence of VVC can occur in women with HIV^{Footnote 8Footnote 9Footnote 10Footnote 11}.

Common STI-associated etiology

The most common STI-associated cause of vaginitis is trichomoniasis, caused by Trichomonas vaginalis, a protozoan.

Vaginal discharge may also be associated with cervicitis caused by Neisseria gonorrhoeae (GC) or Chlamydia trachomatis (CT). Refer to the Gonococcal Infections and Chlamydial Infections (including LGV) guides, or the Cervicitis section of this guide, as appropriate.

Clinical manifestations

Symptoms and signs of trichomoniasis include:

• Off-white or yellow, frothy vaginal discharge, often profuse
• Erythema of vulva and cervix ("strawberry cervix")
• Itch
• Dysuria

In women, 10-50% of trichomoniasis infections are asymptomatic^{Footnote 12}.

Most men with trichomoniasis are asymptomatic, but some may have mild urethritis^{Footnote 12}.

Diagnostic testing

Recommended testing for trichomoniasis:

• Obtain vaginal swab, cervical swab or urine for nucleic acid amplification testing (NAAT) to detect T. vaginalis
  • NAAT is the most sensitive and specific assay for detecting T. vaginalis ^{Footnote 13Footnote 14Footnote 15}
  • Consult local laboratory for testing options for T. vaginalis
• Obtain sample of discharge from vaginal wall for point of care microscopy (where available) for wet mount, Gram stain, and whiff test (optional)
  • Examine for motile flagellated protozoa, trichomonads and polymorphonuclear leukocytes (PMN)
  • Clue cells*, budding yeast, pseudohyphae, PMN, Gram-negative intracellular diplococci and decreases in normal flora of lactobacilli may be useful findings for the differential diagnosis of VVC, BV or GC
  • Positive whiff test is indicative of BV
• Measure vaginal pH with narrow-range pH paper
  • Results >4.5 are indicative of trichomoniasis or BV
• Obtain cervical swab for NAAT for CT and GC, plus culture for GC (where available)
  • Vaginal swabs or first-void urine (FVU) are also appropriate specimens for NAAT
  • Vaginal swabs for culture for GC are not recommended^{Footnote 16}

Vaginal infections can cause signs and symptoms that are similar to those of cervicitis. If cervicitis is suspected, refer to the Cervicitis section of this guide.

* Clue cells are epithelial cells covered in coccobacilli.

Empiric treatment and management

The decision to treat trichomoniasis empirically or to wait for test results should reflect the:

• Severity of the clinical condition
• Probability of infection
• Person's risk factors for a sexually transmitted or blood-borne infection (STBBI)
• Person's willingness to abstain from sex and to return for test results or follow-up

Empiric Treatment for trichomoniasis
Non-pregnant people	Metronidazole 2 g PO in a single dose [A-l] or Metronidazole 500 mg PO BID for 7 days [A-l] Notes: Efficacy is 82-88% for both regimens; increases to 95% if partner also treatedFootnote 17 Intravaginal metronidazole gel is not effective Prevalence of metronidazole-resistant T. vaginalis is estimated at 5%; it usually responds to high-dose metronidazoleFootnote 18
Pregnant people	Metronidazole 2 g PO in a single dose for symptom relief [A-l]. Notes: Metronidazole 500 mg PO BID for 7 days [A-l] is an alternate treatment in pregnancy. It is not recommended that those who are asymptomatic during pregnancy be treated [D-l]Footnote 19. It is not known whether treatment will improve pregnancy outcomesFootnote 4Footnote 5.

Treat current sexual partners with the same empiric treatment regimen as the index case.

Follow-up

No follow-up is necessary for trichomoniasis, unless symptoms persist or recur (usually due to reinfection).

In the case of suspected or confirmed gonorrhea or chlamydia (including LGV), consult etiology specific guides for treatment, follow-up and test of cure (TOC) recommendations.

Reporting and partner notification

Trichomoniasis is reportable in certain provinces and territories. Refer to the local public health authority for information on reporting requirements for trichomoniasis.

When treatment is indicated for other STIs: notify, evaluate, test and treat (as appropriate) sexual partners. Refer to the etiology-specific guide(s) for guidance on reporting and partner notification.