What is the recommended treatment for an isolated HSV‑2 infection in an adult?

Treatment of Isolated HSV-2 Infection in Adults

For an isolated HSV-2 infection in an immunocompetent adult, initiate oral antiviral therapy immediately with valacyclovir 1 gram twice daily for 7–10 days, or acyclovir 400 mg three times daily for 7–10 days. 1

First-Episode Treatment Algorithm

Primary regimens:

• Valacyclovir 1 gram orally twice daily for 7–10 days (preferred for convenience) 1
• Acyclovir 400 mg orally three times daily for 7–10 days (alternative with extensive safety data) 1
• Famciclovir 250 mg orally three times daily for 7–10 days (alternative option) 1

Extend therapy beyond 10 days if healing is incomplete at the end of the initial treatment course. 1

Severe Disease Requiring Hospitalization

For patients with severe mucocutaneous lesions, disseminated infection, encephalitis, pneumonitis, or hepatitis, initiate intravenous acyclovir 5–10 mg/kg every 8 hours until lesions begin to regress, then transition to oral therapy. 2, 1

Monitor renal function at baseline and once or twice weekly during IV therapy due to nephrotoxicity risk. 1

Critical Patient Counseling at Initial Diagnosis

Patients must understand the following key points:

• HSV-2 is a chronic, lifelong infection with potential for recurrent episodes despite treatment. 1
• Asymptomatic viral shedding occurs and transmission can happen even without visible lesions. 1
• Abstain from all sexual activity when lesions or prodromal symptoms are present. 2, 1
• Use condoms consistently during all sexual encounters with new or uninfected partners, as this reduces transmission risk by approximately 50%. 1
• Women of childbearing age must inform their obstetric providers about HSV-2 infection to allow appropriate pregnancy management. 2, 3

Planning for Recurrent Episodes

Provide a prescription for episodic therapy at the initial visit so patients can self-initiate treatment at the first sign of recurrence. 4 Treatment is most effective when started during the prodromal period or within 24 hours of lesion onset. 1, 4

Episodic therapy options for recurrences:

• Valacyclovir 500 mg orally twice daily for 3–5 days 1
• Acyclovir 400 mg orally three times daily for 5 days 1
• Famciclovir 125 mg orally twice daily for 5 days 4

When to Consider Suppressive Therapy

Offer daily suppressive therapy to patients experiencing ≥6 recurrences per year, as this reduces outbreak frequency by ≥75% and decreases asymptomatic viral shedding. 1, 3

Suppressive regimens for immunocompetent adults:

• Valacyclovir 500 mg once daily (for infrequent recurrences <10 episodes/year) 1, 3
• Valacyclovir 1000 mg once daily (for frequent recurrences ≥10 episodes/year) 1, 3
• Acyclovir 400 mg twice daily (alternative with documented safety for up to 6 years) 1, 3

After 1 year of continuous suppressive therapy, discontinue treatment temporarily to reassess the patient's natural recurrence rate, as outbreak frequency often decreases over time. 1, 3

Special Populations

HIV-Infected Patients

HIV-infected adults require higher dosing and longer duration:

• For first episodes, use the same regimens as immunocompetent patients but consider extending duration. 1
• For suppressive therapy, use valacyclovir 500 mg twice daily (not once daily). 1, 3
• Never use short-course therapy (1–3 days) in HIV-infected patients, as it is ineffective. 1
• Suppressive therapy reduces HIV RNA concentrations in plasma and genital secretions, though the direct clinical benefit remains uncertain. 1

Pregnant Women

Acyclovir is the preferred antiviral during pregnancy based on decades of safety data showing no increased risk of major birth defects. 1, 3

Episodic therapy for first-episode or recurrent HSV during pregnancy may be offered, but routine suppressive therapy is not recommended unless the patient has frequent or severe recurrences. 1, 3

For women with a history of genital herpes, consider suppressive therapy starting at 36 weeks gestation to reduce HSV shedding at delivery and decrease the need for cesarean delivery. 1

Cesarean delivery is mandatory for women with visible genital lesions or prodromal symptoms at the onset of labor. 1

Renal Impairment

For patients with creatinine clearance <30 mL/min, reduce valacyclovir to 500 mg every 24–48 hours; no adjustment is needed for CrCl 30–49 mL/min. 3

Monitor renal function in patients with substantial renal impairment receiving any antiviral therapy. 1

Management of Treatment Failure

Suspect antiviral resistance if lesions do not begin to resolve within 7–10 days of appropriate therapy. 1, 3

Obtain viral culture with susceptibility testing to confirm HSV etiology and document resistance. 1

For confirmed acyclovir-resistant HSV (all acyclovir-resistant strains are also resistant to valacyclovir and famciclovir), switch to intravenous foscarnet 40 mg/kg every 8 hours until complete clinical resolution. 1, 3

Resistance rates in immunocompetent patients remain <0.5%, but rise to 5–7% in HIV-infected or immunocompromised individuals. 1, 3

Common Pitfalls to Avoid

• Never use topical acyclovir alone, as it is substantially less effective than systemic therapy and does not improve systemic symptoms. 2, 1, 4
• Do not assume suppressive therapy eliminates transmission risk—counsel patients that asymptomatic shedding persists despite treatment. 1, 3
• Do not use valacyclovir 8 grams per day in immunocompromised patients due to risk of thrombotic thrombocytopenic purpura/hemolytic uremic syndrome. 3
• Do not delay treatment for recurrences beyond 72 hours, as efficacy decreases significantly after this window. 4

Partner Management

Sex partners should be evaluated and counseled, even if asymptomatic. 2

Symptomatic partners should receive the same treatment as any patient with genital lesions. 2

Asymptomatic partners should be queried about histories of typical and atypical genital lesions and encouraged to self-examine for future lesions. 2