Herpes Simplex Virus - HSV

 

Clinical Background

Herpes simplex virus (HSV) occurs worldwide and produces a variety of clinical manifestations, ranging from mild stomatitis to fatal disease.

Epidemiology

  • Prevalence
    • Types 1 (HSV-1) and 2 (HSV-2)
      • HSV-1 – 70-80% seropositivity in U.S. adults; 100% positivity in undeveloped countries
      • HSV-2 – 10-40% seropositivity in U.S. adults
  • Age – 33% of cases <20 years; 50% of cases >50 years
  • Sex – M<F (HSV-2)
  • Transmission
    • HSV-1 – oral predominantly
    • HSV-2 – sexual predominantly (can occur during asymptomatic periods)
    • Vertical transmission
  • Ethnicity – more often found in African Americans

Organism

  • Double-stranded DNA virus of the Herpesviridae family
    • HSV-1 – majority of nongenital HSV infections
    • HSV-2 – cause of genital infections in >80% of patients
  • Biological features unique to herpes virus
    • Latency
    • Reactivation

Risk Factors

  • HSV-1
    • Lower socioeconomic status
  • HSV-2
    • High number of sexual partners
    • Previous history of sexually transmitted infections
    • Early age at first sexual experience
    • Lower socioeconomic status
    • Older age
    • Female
    • Black race

Clinical Presentation

  • Manifestations and clinical course of HSV depend on clinical site, age and immune status of host
  • Only 10-30% of new infections are symptomatic
  • HSV-2 causes recurrent genital herpes episodes more often than HSV-1
  • Primary infections are usually longer in duration than reactive infections
  • Common clinical syndromes
    • Gingivostomatitis – widespread oral ulcers with lymphadenopathy
    • Recurrent herpes labialis – erythematous papules and vesicles on lips
    • Keratitis – corneal ulcers; can lead to blindness
    • Conjunctivitis – increases risk of keratitis
    • Vesicular skin eruptions usually in face, ears and neck areas (herpes gladiatorum); dissemination of oral herpes into a previously abnormal skin area (burns, atopic dermatitis; referred to as eczema herpeticum)
    • Herpetic whitlow – vesicular eruption located on pulp of distal phalanges of hands
    • Aseptic meningitis and recurrent meningitis (Mollaret meningitis)
      • Occurs as a complication of HSV-1 or HSV-2 primary infection
    • Primary and recurrent genital herpes
      • Increases risk for acquiring HIV
      • Usually presents as symptomatic and painful genital ulcer
    • Visceral herpes (esophagitis, pneumonitis, hepatitis) – more common in immunocompromised patients
    • Meningoencephalitis – associated with focal neurologic findings
    • Neonatal herpes – infection may be acquired in utero, intrapartum, or postnatally
      • Encephalitis
      • Disseminated infection
      • Localized disease
      • Congenital – microcephaly, hydrocephalus, retinitis, cutaneous vesicular lesions
      • Pregnancy
        • Disease has higher rate of dissemination
        • More commonly associated with visceral involvement
    • Proctitis – most common in homosexual men

Treatment

  • Suppressive therapy may be useful in treating repeated reactivation infections
  • Antiviral therapy (acyclovir, valacyclovir, or famciclovir) indicated for both primary and recurrent genital HSV infection
  • Intravenous acyclovir therapy indicated in patients with severe HSV disease and with complications such as disseminated infection, pneumonitis, hepatitis, and encephalitis
  • Intravenous foscarnet or topical cidofovir gel may be used in acyclovir-resistant refractory mucocutaneous HSV infections

Prevention

  • Barrier contraception and daily suppressive therapy recommended to prevent infecting partner with genital herpes
  • Pregnant women not infected with HSV-2 should be advised to avoid intercourse during the third trimester with men who have genital herpes