Parameter | Normal findings | Vulvovaginal candidiasis | Bacterial vaginosis | Trichomoniasis |
Symptoms | None or mild, transient | Pruritus, soreness, dyspareunia | Malodorous fishy discharge, no dyspareunia | Malodorous discharge, burning, postcoital bleeding, dyspareunia, dysuria |
Signs | Normal vaginal discharge consists of 1 to 3 mL fluid (per 24 hours), which is white or transparent, thin or thick, and mostly odorless | Vulvar erythema and/or edema Discharge may be white and clumpy and may or may not adhere to vagina | Off-white/gray thin discharge that coats the vagina | Thin green-yellow discharge, vulvovaginal erythema |
Vaginal pH | 4.0 to 4.5* | 4.0 to 4.5 | >4.5 | >4.5¶ |
Amine test | Negative | Negative | Positive (in 70 to 80% of patients) | Often positive |
Saline microscopy | PMN:EC ratio <1; rods dominate; squames +++ | PMN:EC ratio <1; rods dominate; squames +++; pseudohyphae (present in approximately 40% of patients); budding yeast for nonalbicans Candida | PMN:EC <1; loss of rods; increased coccobacilli; clue cells comprise at least 20% of epithelial cells (present in >90% of patients) | PMN ++++; mixed flora; motile trichomonads (present in approximately 60% of patients) |
10% potassium hydroxide microscopy | Negative | Pseudohyphae (in approximately 70% of patients) | Negative | Negative |
Other tests | – | If microscopy nondiagnostic:
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| If microscopy nondiagnostic:
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Differential diagnosis | Physiologic leukorrhea | Contact irritant or allergic vulvar dermatitis, chemical irritation, focal vulvitis (vulvodynia) | Elevated pH in trichomoniasis, atrophic vaginitis, and desquamative inflammatory vaginitis | Purulent vaginitis, desquamative inflammatory vaginitis, atrophic vaginitis, erosive lichen planus |
EC: vaginal epithelial cells; PMN: polymorphonuclear leukocytes; squames: squamous vaginal epithelial cells.
* pH >4.5 is normal for patients with low levels of estrogen, including those who are premenarchal; postpartum; lactating; postmenopausal (without estrogen use); or using estrogen-blocking drugs, such as aromatase inhibitors.
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