What could be causing my recurrent vulvar shingles outbreaks, given that I'm experiencing my second episode in 3 months with moderate stress and no underlying illness?

Recurrent Vulvar Lesions: Differential Diagnosis

You most likely have recurrent genital herpes (HSV), not shingles, and should start suppressive antiviral therapy immediately given your frequent recurrences.

Critical Diagnostic Clarification

Shingles (herpes zoster) on the vulva is extremely rare and almost never recurs in the same location within 3 months 1, 2. True shingles:

• Follows a dermatomal distribution (typically S2-S3 for vulvar involvement) 2
• Occurs once in a lifetime in the same dermatome in immunocompetent individuals 1
• Recurrence within 3 months strongly suggests misdiagnosis 2

Your recurrent vulvar lesions are almost certainly genital herpes (HSV-2 or HSV-1), not shingles 3, 4. This is critical because:

• Genital herpes commonly recurs multiple times per year, especially with HSV-2 3, 4
• Stress is a well-documented trigger for HSV recurrences 3
• Labial location is classic for genital herpes 3, 4

Immediate Treatment Recommendation

With two episodes in 3 months (≥6 episodes per year projected), you meet criteria for daily suppressive therapy 3, 4:

First-line suppressive regimen:

• Valacyclovir 500 mg orally once daily 3, 5
• Alternative: Valacyclovir 1 gram orally once daily 3, 4
• Alternative: Acyclovir 400 mg orally twice daily 3, 4

Suppressive therapy reduces recurrence frequency by ≥75% 3, 4, 6 and should be continued for at least 6-12 months before reassessing recurrence patterns 3.

For Current Outbreak (Episodic Treatment)

Start treatment immediately at first sign of symptoms 3, 4:

• Valacyclovir 500 mg orally twice daily for 5 days 3, 4
• Alternative: Acyclovir 400 mg orally three times daily for 5 days 3, 4
• Alternative: Famciclovir 125 mg orally twice daily for 5 days 3, 4

Treatment is most effective when started during prodrome or within 1 day of lesion onset 3, 6.

Other Diagnostic Considerations

While HSV is overwhelmingly likely, other vulvar conditions to exclude include:

Non-infectious vulvar dermatoses 7:

• Lichen sclerosus (most common vulvar dermatosis, 64.7% in specialized clinics) 7
• Lichen planus 7
• Contact dermatitis 8, 9

Infectious causes 8, 9:

• Recurrent candidiasis (though typically presents with discharge and itching, not discrete lesions) 10
• Bacterial infections 8

Key distinguishing features:

• HSV presents with painful vesicles/ulcers that recur in similar locations 3, 4
• Candidiasis presents with thick white discharge, pruritus, and erythema 10
• Dermatoses present with chronic changes (whitening, scarring, erosions) rather than acute vesicular outbreaks 7

Critical Next Steps

1. Confirm diagnosis with type-specific HSV serology if not previously done 3
2. Start suppressive therapy immediately given frequency of recurrences 3, 4
3. Counsel on transmission risk: Asymptomatic viral shedding can occur; use condoms with new/uninfected partners 3, 4
4. Abstain from sexual activity when lesions or prodromal symptoms present 3, 4

Important Caveats

• If you are immunocompromised (HIV, on immunosuppressants like infliximab), vulvar herpes zoster becomes more plausible and may require different management 2
• If symptoms persist beyond 5 days of antiviral therapy, consider viral resistance testing or alternative diagnoses 3
• Topical acyclovir is substantially less effective than oral therapy and should not be used 4, 6
• After 1 year of suppressive therapy, consider discontinuation to reassess natural recurrence frequency 3