Acyclovir is the Most Appropriate Treatment
For this patient with a first clinical episode of genital herpes, acyclovir is the definitive treatment of choice (Answer A). The clinical presentation of a painful genital vesicle with bilateral inguinal lymphadenopathy in a sexually active young woman is classic for genital herpes simplex virus (HSV) infection, even with a negative Tzanck smear.
Clinical Reasoning
The negative Tzanck smear does not rule out HSV infection—this test has poor sensitivity and frequently produces false negatives. The negative VDRL excludes syphilis. The clinical picture strongly suggests first-episode genital herpes:
- Painful vesicular lesion (HSV lesions are characteristically painful, unlike chancroid or syphilis)
- Bilateral inguinal lymphadenopathy (common in primary HSV)
- Sexually active patient
- Negative syphilis testing
Treatment Recommendation
The CDC guidelines consistently recommend acyclovir as the first-line treatment for first clinical episodes of genital herpes 1, 2. The specific regimens are:
- Acyclovir 400 mg orally three times daily for 7-10 days, OR
- Acyclovir 200 mg orally five times daily for 7-10 days 2
The 400 mg three-times-daily regimen is more practical for patient adherence due to less frequent dosing 2.
Why Other Options Are Incorrect
Ceftriaxone (B): Used for gonorrhea or chancroid, not HSV. Chancroid typically presents with painful ulcers (not vesicles) and unilateral lymphadenopathy.
Foscarnet (C): Reserved exclusively for acyclovir-resistant HSV in immunocompromised patients 3. This immunocompetent patient should receive standard acyclovir first.
Ribavirin (D): Not indicated for HSV infection—used for viral hemorrhagic fevers and hepatitis C.
Vancomycin (E): An antibiotic for gram-positive bacteria, completely inappropriate for viral infection.
Important Clinical Considerations
Treatment should be initiated immediately based on clinical diagnosis without waiting for confirmatory testing 2. The guidelines emphasize that systemic acyclovir provides partial control of symptoms and signs when used to treat first clinical episodes 1.
Key counseling points for this patient:
- Genital herpes is a recurrent, incurable viral disease
- Asymptomatic viral shedding occurs and can transmit infection
- Abstain from sexual activity while lesions are present
- Use condoms during all sexual exposures
- Inform future healthcare providers, especially if pregnancy occurs 1, 2
The patient should be advised that treatment may need to be extended beyond 10 days if healing is incomplete 2. Follow-up should assess for recurrences and discuss suppressive therapy options if frequent recurrences develop (≥6 per year).