From the Guidelines
Vulvovaginal fungal infections can be accurately diagnosed using polymerase chain reaction (PCR) with high clinical accuracy (sensitivity 90.9%, specificity 94.1%, PPV 87.8%, and NPV 95.7%) 1. To distinguish between vulvovaginal fungal and bacterial infections, it is essential to consider their symptoms and laboratory findings. Fungal infections, such as vulvovaginal candidiasis (VVC), typically present with:
- Thick, white, cottage cheese-like discharge
- Intense itching
- Vulvar redness
- Sometimes burning with urination Examination may reveal erythema and edema of the vulva and vaginal walls. Laboratory diagnosis includes:
- Microscopy with KOH preparation showing pseudohyphae or yeast buds
- A normal vaginal pH (<4.5)
- Fungal culture if needed In contrast, bacterial vaginosis (BV) presents with:
- Thin, grayish-white, homogeneous discharge with a fishy odor, especially after intercourse or during menstruation
- Patients often report minimal itching or irritation Laboratory findings include:
- Vaginal pH >4.5
- Positive whiff test (fishy odor when KOH is added to discharge)
- Clue cells (epithelial cells covered with bacteria) on wet mount microscopy
- Gram stain showing decreased lactobacilli and increased anaerobic bacteria supports BV diagnosis Treatment for VVC includes antifungal medications like fluconazole 150mg orally once or topical azoles, such as clotrimazole 1% cream 5 g intravaginally for 7–14 days, while BV requires antibiotics such as metronidazole 500mg twice daily for 7 days or clindamycin cream 1. Accurate diagnosis through both clinical assessment and laboratory testing is essential for appropriate treatment selection. It is also important to note that some commercially available PCR tests for yeast are not Food and Drug Administration (FDA) approved, and clinicians should be aware of this when selecting diagnostic tests 1.
From the FDA Drug Label
A clinical diagnosis of bacterial vaginosis was based on Amsel's criteria and defined by the presence of an abnormal homogeneous vaginal discharge that (a) has a pH of greater than 4.5, (b) emits a "fishy" amine odor when mixed with a 10% KOH solution, and (c) contains ≥20% clue cells on microscopic examination. A microbiologic diagnosis of bacterial vaginosis was based on Gram stain of the vaginal smear demonstrating (a) markedly reduced or absent Lactobacillus morphology, (b) predominance of Gardnerella morphotype, and (c) absent or few white blood cells, with quantification of these bacterial morphotypes to determine the Nugent score, where a score ≥4 was required for study inclusion and a score of 0 to 3 considered a microbiologic cure.
The symptoms of bacterial vaginosis include:
- Abnormal homogeneous vaginal discharge
- Vaginal discharge pH of greater than 4.5
- "Fishy" amine odor when mixed with a 10% KOH solution
- ≥20% clue cells on microscopic examination
The labs for bacterial vaginosis include:
- Gram stain of the vaginal smear
- Nugent score ≥4
There is no information in the provided drug label about vulvovaginal fungal infections. 2
From the Research
Symptoms of Vulvovaginal Fungal and Bacterial Infections
- Vulvovaginal candidiasis (VVC) symptoms include inflammation and discharge, affecting 75% of women at least once 3
- Recurrent VVC is defined as 4 or more episodes per year 3
- Trichomoniasis is a common non-viral sexually transmitted infection, with symptoms including vaginal discharge and itching 3
- Bacterial vaginosis (BV) symptoms include abnormal vaginal discharge and odor 3
Laboratory Diagnosis
- VVC can be diagnosed through clinical evaluation and mycological testing, including wet mount and fungal culture 4
- Trichomoniasis can be detected by antigen testing using vaginal swabs and evaluated by immunoassay or nucleic acid amplification test 3
- BV can be diagnosed using either clinical (Amsel's) or laboratory (Gram stain with objective scoring system) criteria 3
Treatment Options
- VVC can be treated with topical and oral antifungal azole medications, including fluconazole and clotrimazole 5, 3, 6, 7
- Recurrent VVC can be treated with maintenance therapy, including weekly oral fluconazole for up to 6 months 3
- Trichomoniasis can be treated with oral metronidazole, with cure rates of up to 88% 3
- BV can be treated with oral metronidazole, with alternatives including vaginal metronidazole gel and oral or vaginal clindamycin cream 3