Evaluation of vaginal discharge
Abnormal vaginal discharge is triaged at the bedside with vaginal pH, the amine whiff test, and saline/KOH microscopy, and treated with metronidazole for bacterial vaginosis or trichomoniasis, fluconazole or clotrimazole for candidiasis, and ceftriaxone plus doxycycline for cervicitis.
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What this article covers
- Overview
A symptom, not a diagnosis: abnormal vaginal discharge, odor, itching, or irritation is separated into distinct causes with pH, the amine whiff test, and microscopy.
- Epidemiology
Bacterial vaginosis is the most common vaginal infection in women of childbearing age.
- Risk factors
New or multiple sexual partners and unprotected intercourse raise risk for bacterial vaginosis, trichomoniasis, cervicitis, and other STIs including human immunodeficiency virus (HIV).
- Pathophysiology
Bacterial vaginosis: lactobacilli-dominant flora shifts to polymicrobial anaerobic overgrowth (Gardnerella, Atopobium, Prevotella, Mobiluncus), raising vaginal pH and producing the amines behind the fishy odor.
- Clinical features
Bacterial vaginosis: painless, thin, homogeneous grayish-white discharge coating the vaginal walls with a fishy odor, often noticed after intercourse; no significant vulvar inflammation.
- Differential diagnosis
Bacterial vaginosis: pH 4.5, positive whiff test, clue cells on saline wet mount, no vulvar inflammation.
- Diagnosis
This is established by a stepwise bedside evaluation, not one test: speculum exam to locate the discharge source, vaginal fluid pH, the amine (KOH) whiff test, and saline/KOH wet-mount microscopy…
- Management
First, remove any structural cause: remove a retained foreign body (tampon, pessary, condom) immediately.
- Complications
Toxic shock syndrome from a retained tampon can progress to septic shock, multiorgan dysfunction (renal injury, thrombocytopenia, transaminitis), and death if not addressed promptly.
- Prognosis
Uncomplicated bacterial vaginosis, candidiasis, and trichomoniasis resolve with single-course therapy in most patients, though recurrence is common.
- Prevention
Avoid vaginal douching, which disrupts protective lactobacilli and raises bacterial vaginosis risk.
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Related articles
- Bacterial vaginosis
Bacterial vaginosis is a polymicrobial dysbiosis of the vagina caused by loss of lactobacilli and anaerobic overgrowth, diagnosed clinically by the Amsel criteria and treated with oral or intravaginal metronidazole or clindamycin.
- Vulvovaginal candidiasis
Candida vulvovaginitis presents with vulvar itching, burning, and thick curdy white discharge at a normal vaginal pH; uncomplicated disease clears with a single 150 mg oral fluconazole dose or a short topical azole course, while complicated or recurrent disease needs a longer induction course followed by suppressive therapy.
- Trichomonas vaginalis infection
Trichomonas vaginalis is a flagellated protozoan sexually transmitted infection that presents with malodorous frothy yellow-green discharge and a strawberry cervix but is frequently asymptomatic, especially in men. Diagnosis rests on nucleic acid amplification testing of vaginal secretions, and treatment is a single 2 g oral dose of metronidazole or tinidazole with partner treatment and retesting in 3 months for high reinfection rates.
- Vaginal foreign bodies
A retained object in the vagina, most often a forgotten tampon in a reproductive-age patient or a small toy or paper wad in a prepubertal child, presents with malodorous purulent discharge and can seed staphylococcal toxic shock syndrome; management is removal plus, if the TSS triad is present, vancomycin and clindamycin.
- Acute cervicitis
Acute cervicitis is inflammation of the uterine cervix diagnosed by visualized mucopurulent endocervical discharge or a friable os that bleeds with a swab, most often caused by Neisseria gonorrhoeae or Chlamydia trachomatis, treated empirically at the same visit while nucleic acid amplification testing is pending.
- Pelvic inflammatory disease
Pelvic inflammatory disease is an ascending polymicrobial infection of the upper female genital tract, most often caused by Neisseria gonorrhoeae, Chlamydia trachomatis, or Mycoplasma genitalium, diagnosed clinically on uterine, adnexal, or cervical motion tenderness. Most women are treated as outpatients with a single dose of ceftriaxone plus 14 days of doxycycline, while parenteral cefotetan or cefoxitin plus doxycycline, or clindamycin plus gentamicin, is reserved for hospitalized patients, with tubo-ovarian abscess and infertility among the major complications of delayed treatment.
- Staphylococcal toxic shock syndrome
Staphylococcal toxic shock syndrome is a multisystem, toxin-mediated illness caused by TSST-1-producing Staphylococcus aureus acting as a superantigen, classically linked to prolonged tampon use, nasal packing, or a focal staphylococcal infection, diagnosed by a clinical case definition of fever, hypotension, diffuse desquamating rash, and involvement of three or more organ systems, and treated with source control plus antistaphylococcal antibiotics including clindamycin.