What is the appropriate diagnosis and treatment for a female patient presenting with vulvar itchiness and thick discharge, with a normal urinalysis result?

Vulvovaginal Candidiasis: Diagnosis and Treatment

This patient most likely has vulvovaginal candidiasis (VVC), which presents with vulvar itching and thick white discharge with normal urinalysis, and should be confirmed with microscopy or culture before treating with topical azoles or oral fluconazole 150 mg as a single dose. 1, 2

Why Candidiasis is the Leading Diagnosis

The clinical presentation strongly suggests VVC based on:

• Thick discharge with vulvar itching are the hallmark symptoms of candidiasis, which affects approximately 75% of women at least once in their lifetime 1, 2
• Normal urinalysis effectively rules out urinary tract infection and makes bacterial causes less likely, as candidiasis maintains a normal vaginal pH (<4.5) unlike bacterial vaginosis or trichomoniasis which elevate pH above 4.5 1, 2, 3
• The absence of malodorous discharge makes bacterial vaginosis (which produces a fishy odor) and trichomoniasis (which produces foul-smelling discharge) less likely 1

Diagnostic Confirmation Required Before Treatment

Do not treat based on clinical appearance alone—microscopy or culture is mandatory: 2

• Perform wet preparation with 10% KOH to visualize yeast or pseudohyphae, which confirms the diagnosis 1, 2, 3
• If microscopy is negative but clinical suspicion remains high, culture is more sensitive than microscopic examination and should be obtained 1, 2
• Measure vaginal pH—a pH <4.5 supports candidiasis, while pH >4.5 suggests bacterial vaginosis or trichomoniasis 1, 2, 3

Treatment Recommendations

For Uncomplicated VVC (First-Line Options):

• Oral fluconazole 150 mg as a single dose achieves 55% therapeutic cure rate (complete symptom resolution plus negative culture) and 69% clinical cure rate 1, 4
• Short-course topical azoles (3-7 days) result in 80-90% relief of symptoms and negative cultures in patients who complete therapy 1, 3
• Both oral and topical treatments are equally effective for uncomplicated cases 1, 3, 5

Special Considerations:

• If pregnant: Only 7-day topical azole therapies are recommended—oral fluconazole is contraindicated 1, 4
• If symptoms persist or recur within 2 months: Return for follow-up evaluation, as this may indicate complicated VVC requiring longer treatment duration 1
• Treatment of sex partners is not necessary for VVC, as it is not primarily sexually transmitted 1, 5

Critical Pitfall: Consider Missed Bacterial Vaginosis

If testing confirms candidiasis is not present, bacterial vaginosis remains the most likely diagnosis despite initial negative testing:

• Standard clinical testing misses BV in 20-30% of cases, and BV accounts for 40-50% of vaginitis when a cause is identified 6, 3
• Up to 50% of women with BV meeting diagnostic criteria are asymptomatic or have atypical presentations 6
• Retest using Gram stain with Nugent criteria (90% sensitivity) or DNA probe testing for Gardnerella vaginalis if initial testing was negative 6, 7
• While BV classically produces gray discharge, it can produce white discharge similar to candidiasis 6

If BV is Confirmed on Retesting:

• Metronidazole 500 mg orally twice daily for 7 days achieves 80-90% cure rates 6, 3, 5
• Counsel patients that BV has a 50-80% recurrence rate within one year 6

Common Diagnostic Pitfalls to Avoid

• Laboratory testing fails to identify a cause in a substantial minority of women with vaginitis symptoms—do not assume negative testing rules out infection 1, 7
• White discharge color is non-specific—while candidiasis classically presents with thick white "cottage cheese" discharge, BV can also produce white or gray discharge 6, 8
• Consider mechanical or chemical irritation from soaps or hygiene products if objective vulvar inflammation is present without identified pathogens 1, 7