Herpes Simplex



  • Characteristic vesicular rash primarily located in oral and genital regions caused by infection with HSV-1 and HSV-2
  • Historically, HSV-1 and HSV-2 caused infection in different areas: HSV-1 in the lips, mouth, face, and eyes and HSV-2 in the genitals. At present, primary genital infection with HSV-1 is as common as with HSV-2.
  • Wide range of sequelae, impacted by 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.


Affects all ages; most HSV-1 is acquired in childhood, and most HSV-2 is acquired in young–middle adulthood.

>1 million new cases of HSV per year


  • Widespread; 1–25% of adults may shed HSV-1 or HSV-2. Many are unaware of their infection status.
  • Prevalence of antibodies to HSV-1 is 90% by adulthood in the general population; 33% of the population infected by age 5 years
  • 30% of adults have antibodies to HSV-2.
  • According to the WHO, about 417 million people worldwide, ages 15 to 49 years are affected by HSV-1.
  • 400 million people have genital herpes caused by HSV-2.
  • 1 in 5 pregnant women are seropositive for 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 can occur vertically during childbirth.

Risk Factors

  • Immunocompromised state: advanced age, chemotherapy, malignancy, or chronic diseases such as diabetes or AIDS
  • Atopic eczema, especially in children
  • Sexual intercourse with infected person (Condoms minimize 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: usually via vaginal birth; greatest risk 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%
  • Herpes gladiatorum: contact with abrasion sites, often acquired through high-contact sports (such as rugby and wrestling)

General Prevention

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

Commonly Associated Conditions

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

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