What is the appropriate treatment for an adult patient with a normal immune system presenting with a herpes lesion?

Treatment of Herpes Lesions in Immunocompetent Adults

For an adult patient with a normal immune system presenting with a herpes lesion, oral antiviral therapy should be initiated immediately—the specific agent and duration depend on whether this is genital herpes, herpes labialis (cold sores), or herpes zoster (shingles).

Treatment Algorithm by Lesion Type

Genital Herpes (HSV-1 or HSV-2)

For recurrent episodes:

• Initiate episodic therapy within 6 hours of symptom onset for maximum efficacy 1
• Valacyclovir 500 mg orally twice daily for 5 days is the preferred first-line treatment 1
• Alternative regimens include acyclovir 400 mg orally three times daily for 5 days, acyclovir 800 mg orally twice daily for 5 days, or famciclovir 1000 mg twice daily for 1 day 1, 2
• Treatment initiated during prodrome or within 1 day of lesion onset is most effective 1

For frequent recurrences (≥6 episodes per year):

• Daily suppressive therapy with valacyclovir 1 g orally once daily or valacyclovir 500 mg orally once daily 1
• Alternative suppressive options: acyclovir 400 mg orally twice daily or famciclovir 250 mg orally twice daily 1, 2
• Suppressive therapy reduces recurrence frequency by ≥75% and reduces asymptomatic viral shedding 1
• Safe for up to 6 years with acyclovir and 1 year with valacyclovir 1

Herpes Labialis (Cold Sores)

For recurrent episodes:

• Famciclovir 1500 mg as a single oral dose is the preferred treatment 2
• Therapy should be initiated at the first sign or symptom (tingling, itching, burning, pain, or lesion) 2
• This single-dose regimen reduces median time to healing by 1.3 days compared to placebo 2
• Oral acyclovir or valacyclovir are effective alternatives, though require more frequent dosing 3

Critical caveat: Topical acyclovir, penciclovir, and docosanol are substantially less effective than oral therapy and should not be used as primary treatment 3, 1

Herpes Zoster (Shingles)

For uncomplicated herpes zoster:

• Oral valacyclovir 1000 mg three times daily for 7-10 days is preferred due to superior bioavailability and less frequent dosing 4, 5
• Alternative: acyclovir 800 mg orally five times daily for 7-10 days 4
• Alternative: famciclovir 500 mg every 8 hours for 7 days 2
• Treatment must be initiated within 72 hours of rash onset for optimal efficacy in reducing acute pain, accelerating lesion healing, and preventing postherpetic neuralgia 4
• Continue treatment until all lesions have completely scabbed, not just for an arbitrary 7-day period 4

For severe, disseminated, or complicated herpes zoster:

• Intravenous acyclovir 10 mg/kg every 8 hours is mandatory 4, 6
• Continue IV therapy for at least 7-10 days and until clinical resolution is attained 4
• Monitor renal function at initiation and once or twice weekly during treatment 4, 6

Essential Patient Counseling

For genital herpes patients:

• Counsel that genital herpes is a recurrent, incurable viral disease 1
• Antiviral medications control symptoms but do not eradicate the virus or prevent all recurrences 1
• Abstain from sexual activity when lesions or prodromal symptoms are present 1
• Inform sex partners about having genital herpes 1
• Use condoms during all sexual exposures with new or uninfected partners 1
• Asymptomatic viral shedding can occur, potentially leading to transmission even without visible lesions 7, 1

For herpes zoster patients:

• Avoid contact with susceptible individuals (those who haven't had chickenpox) until all lesions have crusted 4
• Lesions are contagious and can transmit varicella to susceptible individuals 4

Common Pitfalls to Avoid

• Never use topical antivirals as primary therapy—they are substantially less effective than systemic therapy 4, 1, 3
• Do not delay treatment waiting for laboratory confirmation in typical presentations 6
• Do not stop antiviral therapy at exactly 7 days if lesions are still forming or have not completely scabbed (particularly for herpes zoster) 4
• Do not use valacyclovir 8 grams per day—this dose is associated with hemolytic uremic syndrome/thrombotic thrombocytopenic purpura 1
• For herpes zoster, treatment initiated beyond 72 hours has not been established as effective, though may still be considered if new lesions are forming 4, 2

When to Escalate Care

Consider IV acyclovir for:

• Severe mucocutaneous HSV lesions requiring hospitalization 6
• Disseminated herpes infection 4, 6
• CNS involvement 4, 6
• Complicated ocular disease 4
• Lesions that fail to begin resolving within 7-10 days of oral therapy (suspect acyclovir resistance) 4

For proven or suspected acyclovir-resistant strains:

• Foscarnet 40 mg/kg IV every 8 hours until clinical resolution 7, 1