What is the diagnosis and treatment for a patient with vaginal discharge resembling Skittles, potentially indicating bacterial vaginosis, yeast infection, or trichomoniasis?

Vaginal Discharge Described Like "Skittles"

Immediate Diagnostic Approach

The term "Skittles" discharge typically refers to a rainbow-colored or multicolored vaginal discharge, which is most commonly associated with bacterial vaginosis (BV) when the discharge appears grayish-white with a characteristic fishy odor, though the exact color description requires clinical correlation with pH testing and microscopy to differentiate between BV, candidiasis, and trichomoniasis. 1, 2

Essential Bedside Tests

Perform these three simple tests immediately to establish diagnosis:

• Measure vaginal pH using narrow-range pH paper applied directly to vaginal secretions—pH >4.5 indicates BV or trichomoniasis, while pH ≤4.5 suggests candidiasis 1, 2, 3

• Perform whiff test by adding 10% KOH to vaginal discharge—a fishy amine odor confirms BV or trichomoniasis 4, 1, 3

• Examine wet mount microscopy with saline preparation to identify motile trichomonads (trichomoniasis) or clue cells (BV), and KOH preparation to identify yeast or pseudohyphae (candidiasis) 4, 2

Differential Diagnosis Based on Clinical Findings

Bacterial Vaginosis (Most Likely)

• Appearance: Homogeneous, thin, white-gray discharge coating vaginal walls 4, 3
• Odor: Fishy smell, especially after intercourse or with KOH application 4, 5
• pH: >4.5 1, 2
• Microscopy: Clue cells (>20% of epithelial cells with bacteria attached to borders) 4, 5
• Diagnosis requires: 3 of 4 Amsel criteria present 5, 4

Vulvovaginal Candidiasis

• Appearance: Thick, white "cottage cheese" or "curdled" discharge 3, 5
• Symptoms: Intense vulvar itching, burning, vulvar erythema and edema 1, 5
• pH: Normal range 3.8-4.5 1, 5
• Microscopy: Hyphae or budding yeast visible in 50-70% of cases 4, 5

Trichomoniasis

• Appearance: Yellow-green, frothy, profuse discharge 1, 6
• Odor: Foul-smelling 5, 6
• pH: >4.5 (present in 70% of cases) 5
• Microscopy: Motile trichomonads on wet mount (detected in only 50-75% of cases) 4, 5
• Cervical findings: Red punctate lesions ("strawberry cervix") in some cases 4

Treatment Protocols

For Bacterial Vaginosis

First-line treatment is metronidazole 500 mg orally twice daily for 7 days, which achieves a 95% cure rate and is superior to single-dose regimens. 2, 3

• Alternative regimen: Clindamycin cream intravaginally 2
• Critical patient instruction: Avoid all alcohol during treatment and for 24 hours after completion to prevent disulfiram-like reactions 3
• Complete the full 7-day course even if symptoms resolve early to reduce recurrence risk 3

For Vulvovaginal Candidiasis

• Standard treatment: Fluconazole 150 mg orally as a single dose (55% therapeutic cure rate) 1, 2
• Alternative: Intravaginal agents such as clotrimazole, miconazole, terconazole, butoconazole, or tioconazole 1
• For recurrent infections: Fluconazole 150 mg weekly for 6 months to maintain clinical and mycologic control 2, 5

For Trichomoniasis

• Standard treatment: Metronidazole 2 grams orally as a single dose (90-95% cure rate) 2, 6
• Essential: Treat sexual partners simultaneously to prevent reinfection 1, 2, 3
• Treatment failure is usually due to non-treatment of the male partner 5

Critical Pitfalls to Avoid

• Never treat based on symptoms alone—always confirm diagnosis with pH and microscopy, as wet mount can miss trichomoniasis 30-50% of the time 4, 3

• Do not use metronidazole as a single 2-gram dose for BV—it requires a 7-day course for optimal cure rates, unlike trichomoniasis 3

• Do not treat male partners for BV or candidiasis—only trichomoniasis requires partner treatment, as partner treatment does not reduce BV recurrence rates 2, 3

• Avoid douching—it alters normal vaginal flora and increases risk of BV 1

• Do not treat asymptomatic Candida colonization—approximately 10-20% of women have Candida in the vagina without symptoms and do not require treatment 1

When to Reconsider the Diagnosis

• If symptoms persist after treatment, reconsider trichomoniasis even with negative initial wet mount, as microscopy misses it 30-50% of the time 4

• If laboratory testing fails to identify a cause, consider mixed infections, as a substantial minority of women may have concurrent infections 3

• For persistent or recurrent symptoms within 2 months, consider treatment failure, reinfection, or alternative diagnoses such as desquamative inflammatory vaginitis, genitourinary syndrome of menopause, or vulvodynia 7

Follow-Up Recommendations

• No routine follow-up needed if symptoms completely resolve after treatment 2, 3

• Return for evaluation if symptoms persist or recur within 2 months, which may indicate treatment failure or reinfection requiring extended therapy or alternative agents 2, 3

• Recurrence of BV is common (50-80% within one year) but does not change initial management 2, 8