What are the possible causes and recommended treatments for vaginal burning after sexual intercourse?

Vaginal Burning After Sexual Intercourse: Causes and Treatment

Most Common Causes

Vulvovaginal candidiasis (yeast infection) is the most frequent infectious cause of post-coital vaginal burning, accounting for 20-25% of vaginitis cases and presenting with vulvar burning, dyspareunia, and external dysuria. 1

The primary differential diagnosis includes:

• Bacterial vaginosis causes 40-50% of vaginitis cases when a cause is identified, typically presenting with thin gray-white discharge, fishy odor, and vaginal pH >4.5, though burning is less prominent than with candidiasis 2, 3

• Trichomoniasis accounts for 15-20% of cases, characterized by diffuse malodorous yellow-green discharge with vulvar irritation, though symptoms can be minimal 1, 4

• Atrophic vaginitis (genitourinary syndrome of menopause) is common in perimenopausal or postmenopausal women, presenting with vaginal dryness, burning, and dyspareunia 4, 5

• Seminal plasma hypersensitivity is a rare IgE-mediated allergic reaction that begins within seconds to minutes after ejaculation, presenting with localized vulvar and vaginal burning, itching, and swelling 1

• Contact dermatitis from latex condoms, lubricants, spermicides, or fragrant products can cause localized burning and irritation 1, 2

Diagnostic Approach

Measure vaginal pH immediately: pH <4.5 strongly suggests candidiasis, while pH >4.5 indicates bacterial vaginosis or trichomoniasis. 4, 2

• Perform wet-mount microscopy with 10% KOH preparation to identify yeast/pseudohyphae (candidiasis), motile trichomonads (trichomoniasis), or clue cells (bacterial vaginosis) 1, 4

• If microscopy is negative but symptoms persist, obtain vaginal cultures to confirm Candida species and detect non-albicans strains, as microscopy has only 58% sensitivity 4, 2

• Consider nucleic acid amplification testing (NAAT/PCR) for superior sensitivity (90% sensitivity, 94% specificity for Candida) when microscopy is inconclusive 4, 6

• Screen for diabetes, immunosuppression, and recent antibiotic use in patients with recurrent symptoms, as 10.9% of women with candidal vaginitis have undiagnosed diabetes 7, 4

• For suspected seminal plasma hypersensitivity, confirm that condom use prevents symptoms and consider skin prick testing with partner's seminal plasma after screening for viral hepatitis, syphilis, and HIV 1

Treatment Based on Etiology

Vulvovaginal Candidiasis (Uncomplicated)

For uncomplicated candidiasis, use either oral fluconazole 150 mg as a single dose OR short-course topical azoles (1-3 days), which achieve 80-90% cure rates. 1

Recommended topical regimens include:

• Miconazole 2% cream 5g intravaginally for 7 days 1
• Clotrimazole 1% cream 5g intravaginally for 7-14 days 1
• Terconazole 0.8% cream 5g intravaginally for 3 days 1
• Tioconazole 6.5% ointment 5g intravaginally as single application 1

Note: Oil-based creams and suppositories may weaken latex condoms and diaphragms. 1

Recurrent Vulvovaginal Candidiasis

Do not initiate empiric fluconazole maintenance without first confirming the Candida species, as Candida glabrata (present in 10-20% of recurrent cases) is intrinsically resistant to fluconazole. 1, 4

• For confirmed recurrent candidiasis (≥4 episodes/year), use extended initial therapy followed by maintenance regimen with fluconazole, clotrimazole, ketoconazole, or itraconazole for 6 months 1

• For fluconazole-resistant cases or treatment failures, vaginal boric acid is the cheapest and easiest alternative option 6

Bacterial Vaginosis

Treat with oral metronidazole 500mg twice daily for 7 days OR intravaginal metronidazole gel 0.75% once daily for 5 days OR intravaginal clindamycin cream 2% once daily for 7 days. 2, 3

• Seven-day treatment courses are required for maximal effectiveness; shorter courses have higher recurrence rates 3

Trichomoniasis

Treat with oral metronidazole 500mg twice daily for 7 days (NOT single-dose therapy), and treat sexual partners simultaneously to prevent reinfection. 1, 6

Atrophic Vaginitis

For vaginal dryness and burning related to menopause, topical vaginal estrogen products are preferred over systemic therapy. 5, 2

• Vaginal estradiol preparations provide local relief with minimal systemic absorption 5
• Non-hormonal options include vaginal moisturizers and lubricants for women who cannot use estrogen 4

Seminal Plasma Hypersensitivity

Correct and consistent condom use effectively prevents reactions in confirmed seminal plasma hypersensitivity. 1

• Failure of condoms to prevent symptoms suggests either incorrect technique or concurrent latex allergy 1
• Patients should avoid sexual contact without barrier protection and carry epinephrine auto-injectors if systemic symptoms occur 1

Critical Pitfalls to Avoid

• Never rely solely on wet-mount microscopy for Candida diagnosis, as false-negative results are common (only 58% sensitivity) 4

• Do not prescribe over-the-counter antifungal preparations without confirmed diagnosis, as this delays treatment of other etiologies and can lead to adverse outcomes 1

• Avoid single-dose metronidazole for trichomoniasis; 7-day courses are required for adequate cure rates 6

• Do not attribute recurrent symptoms to treatment failure without first reconsidering the diagnosis—consider desquamative inflammatory vaginitis, lichen sclerosus, or vulvodynia 4, 6

• When treatment fails, reassess vaginal pH and obtain cultures before attributing failure to resistance 4

Follow-Up Recommendations

Patients should return for follow-up only if symptoms persist or recur within 2 months of initial treatment. 1

• For persistent symptoms despite appropriate therapy, obtain cultures to identify specific pathogens and consider alternative diagnoses 7, 4

• Evaluate and potentially treat sexual partners in cases of recurrent candidiasis or confirmed trichomoniasis 1