Herpes Simplex

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  • Characteristic vesicular rash primarily located in oral and genital regions as the result of infection with:
    • Herpes simplex virus (HSV)-1 blisters mostly on lips, in mouth, face, eyes
    • HSV-2 primarily genital herpes, although cross-reactivity is common (HSV-1 can cause genital sores through oral–genital contact)
  • Associated with a wide range of sequelae. Complexity and variation of presentation depends on the age and immune status of host, whether the infection is primary or recurrent and the degree of dissemination.
  • Viral shedding is typically greatest in the first (primary) infection and lessens with recurrences.
  • Meningitis/encephalitis and pneumonia are serious systemic manifestations associated with HSV infection.


  • Predominant age: affects all ages; however, most HSV-1 is acquired in childhood, and most HSV-2 is acquired in young–middle adulthood.
  • Predominant sex: male = female

  • >1 million new cases of HSV per year
  • HSV can reactivate, causing recurrent disease.
  • Widespread; 1–25% of adults may shed HSV-1 or HSV-2 at any given time. Many are unaware of their infection status.
  • Prevalence of antibodies to HSV-1 is 90% by adulthood in the general population. 30% of adults have antibodies to HSV-2.

Etiology and Pathophysiology

HSV-1 and HSV-2 are double-stranded DNA viruses from the family Herpesviridae. HSV-1 and HSV-2 are transmitted by contact with infected skin during periods of viral shedding. Transmission also occurs vertically during childbirth. Most often, HSV-1 is associated with oral lesions and HSV-2 with genital lesions.

Risk Factors

  • Immunocompromised state
    • Chemotherapy, malignancy/chronic disease states such as diabetes or AIDS, old age
  • Atopic eczema, especially in children
  • Prior HSV infection
  • Sexual intercourse with infected person (Condoms help minimize HSV transmission, but lesions outside condom-protected areas can spread virus.)
  • Occupational exposure
    • Dental professionals at higher risk for HSV-1 and resulting herpetic whitlow
    • Neonatal herpes simplex: Primary infection is life-threatening and usually acquired by vaginal birth to an infected mother; risk is greatest in mothers with primary genital herpes infection; incubation is usually from 5 to 7 days (rarely 4 weeks); cutaneous, mucous membrane, or ocular signs seen in only 70%

General Prevention

  • If active lesions are present, avoid direct contact with immunocompromised people, elderly, and newborns.
  • Hand hygiene
  • Kissing, sharing beverages, and sharing utensils/toothbrushes can transmit HSV.
  • Genital herpes: Avoid sexual contact if active lesions (herpes simplex is also transmitted when disease appears to be inactive); discuss condom benefits and limits; consider antiviral therapy to reduce viral shedding; encourage safe sex.

Commonly Associated Conditions

  • Erythema multiforme: 50% of cases associated with HSV-1 or HSV-2
  • Screen all severe, treatment-resistant, or unusual HSV for concurrent HIV infection.

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