Yeast Infection Education
What Causes Yeast Infections
Yeast infections (candidiasis) are caused by overgrowth of Candida species, most commonly Candida albicans (responsible for 52-70% of cases), with non-albicans species like C. glabrata increasingly recognized as important pathogens. 1, 2
Key Risk Factors
- Hormonal changes: Pregnancy, oral contraceptive use, and estrogen fluctuations promote fungal overgrowth 3, 4
- Antibiotic use: Disrupts normal vaginal flora, allowing Candida proliferation 4
- Immune suppression: HIV infection (particularly with low CD4+ counts), diabetes, and immunosuppressive medications increase infection risk 1
- Contraceptive use: Shows statistically significant association with vulvovaginal candidiasis 2
Recognizing Symptoms
Vaginal Candidiasis
The most specific symptom is vulvar itching, often accompanied by vaginal soreness, thick white "curd-like" discharge, dyspareunia (painful intercourse), and external dysuria (painful urination). 1, 3, 5
Physical examination reveals vulvar edema, erythema, excoriation, fissures, and characteristic white discharge 1, 3
Oral Candidiasis (Thrush)
White patches on tongue, inner cheeks, or throat that can be scraped off, leaving red areas 1
Skin Candidiasis
Red, itchy rash in warm, moist areas (skin folds, under breasts, groin) with satellite lesions 6
Diagnosis: Don't Treat Without Confirming
Clinical diagnosis alone leads to misdiagnosis in over 50% of cases—always confirm with testing before treating. 5
Essential Diagnostic Steps
- Measure vaginal pH: Normal pH <4.5 indicates VVC; elevated pH (>4.5) suggests bacterial vaginosis or trichomoniasis instead 1, 3, 5
- Wet mount microscopy: Mix vaginal discharge with saline and 10% KOH to visualize yeast, pseudohyphae, or hyphae 1, 5
- Vaginal culture: Mandatory if wet mount is negative but symptoms persist, or for recurrent infections to identify non-albicans species 1, 5
Yeast culture remains the gold standard for definitive diagnosis, particularly for identifying non-albicans species that may not respond to standard therapy. 1, 3
Treatment Options
For Non-Pregnant Women with Uncomplicated VVC
A single 150 mg oral dose of fluconazole achieves >90% cure rates and is the recommended first-line treatment. 1, 5
Alternative topical options (all equally effective): 1
- Clotrimazole 1% cream 5g intravaginally for 7 days
- Miconazole 2% cream 5g intravaginally for 7 days
- Any over-the-counter azole antifungal (1-3 day regimens work for uncomplicated cases)
For Complicated VVC (Severe, Recurrent, or Non-albicans Species)
Use either topical azole therapy for 7-14 days OR fluconazole 150 mg every 72 hours for 3 doses. 1, 5
For Recurrent VVC (≥4 Episodes Per Year)
After 10-14 days of induction therapy with topical or oral azole, prescribe fluconazole 150 mg once weekly for 6 months—this achieves symptom control in >90% of patients. 1, 5
For C. glabrata Infections (Azole-Resistant)
First-line treatment is boric acid 600 mg intravaginally daily for 14 days, as azole therapy frequently fails for this species. 5
Alternative: Nystatin suppositories 100,000 units daily for 14 days 5
For Pregnant Women: Critical Safety Information
ONLY topical azole antifungals are safe during pregnancy—oral fluconazole is contraindicated due to associations with spontaneous abortion, craniofacial defects, and cardiac malformations. 3
Recommended regimens for pregnancy: 3
- Clotrimazole 1% cream 5g intravaginally for 7-14 days
- Miconazole 2% cream 5g intravaginally for 7 days
- Terconazole 0.8% cream 5g intravaginally for 3 days
Seven-day courses are significantly more effective than shorter regimens during pregnancy, achieving 80-90% cure rates. 3
The teratogenic warnings about azoles apply ONLY to systemic (oral) formulations, particularly high-dose fluconazole ≥400 mg/day—topical clotrimazole and other topical azoles are safe throughout pregnancy including the first trimester 3
Prevention Strategies
For All Women
- Avoid unnecessary antibiotic use 4
- Wear breathable cotton underwear and avoid tight-fitting clothing
- Maintain good hygiene but avoid douching (disrupts normal flora)
- Control blood sugar if diabetic 1
For Recurrent Infections
After completing 6-month suppressive fluconazole therapy, consider maintenance strategies including proper hygiene and addressing underlying risk factors. 1, 5
Important Note on Probiotics
No evidence supports the use of probiotics for preventing or treating vulvovaginal candidiasis. 1
When Treatment Fails
If symptoms persist after completing therapy: 3, 5
- Reconsider the diagnosis: Rule out bacterial vaginosis, trichomoniasis, contact dermatitis, or eczema
- Suspect non-albicans species: Obtain culture to identify C. glabrata or other resistant organisms requiring alternative therapy
- Extend treatment duration: Use 7-14 day courses for severe infections
- Check for underlying conditions: Uncontrolled diabetes, immunosuppression, or HIV infection
Special Populations
HIV-Positive Women
Treatment is identical to HIV-negative women, but lower CD4+ counts are associated with increased VVC rates and the infection increases viral shedding. 1
Sexual Partners
Routine treatment of sexual partners is NOT warranted as VVC is not typically sexually transmitted. 3
Only treat partners with symptomatic balanitis (penile inflammation) using topical antifungal agents 3
Asymptomatic Colonization
Do NOT treat asymptomatic colonization—approximately 10-20% of women harbor Candida without symptoms, and treatment is unnecessary. 3
Common Pitfalls to Avoid
- Never treat empirically without confirming diagnosis: Symptoms overlap with bacterial vaginosis and trichomoniasis 5
- Never use oral fluconazole during pregnancy: Stick to topical azoles for 7+ days 3
- Never assume all yeast infections are C. albicans: Non-albicans species (especially C. glabrata) require different treatment approaches 5, 2
- Never ignore treatment failures: Persistent symptoms warrant culture and species identification 3, 5