Herpes Simplex

Description

Herpes simplex virus (HSV) infections, caused by HSV-1 and HSV-2, are highly prevalent worldwide, with most adults carrying antibodies. After primary infection, the virus establishes latency in ganglia and may reactivate with stress, trauma, or immune compromise. Mucocutaneous disease presents as painful vesicles on an erythematous base, most often oral or genital, while less common forms involve the central nervous system (CNS) or eyes. Diagnosis is clinical, supported by polymerase chain reaction (PCR) or culture when needed, and treatment relies on antivirals and supportive care.

Epidemiology

• All ages are affected. HSV-1 is typically acquired in childhood whereas HSV-2 is acquired in young-middle adulthood.
• HSV-1 was once mainly oral/ocular and HSV-2 genital; now HSV-1 causes genital infection as often as HSV-2.
• Incidence and prevalence are declining in high-income countries (1)[C].

Etiology and Pathophysiology

• Enveloped, dsDNA viruses from the family Herpesviridae
• Transmission occurs via direct mucosal/skin contact, saliva, sexual contact, vertical (during delivery), rarely transplacentally.
• Primary infection: The virus enters through mucosa and replicates at the site of contact; replication leads to cell lysis resulting in characteristic vesicles.
• Latency: Virus enters sensory nerve endings and via retrograde transport, establishes latency in sensory ganglion neurons.
• Reactivation: The virus is reactivated and transported to epithelial cells where it continues to replicate and shed, with or without characteristic ulcerations.
  • Triggered by stress, acute illness, trauma, immunodeficiency, etc.
• Dissemination: spreads to atypical sites, including lungs, gastrointestinal tract, CNS, and eyes
  • May occur during pregnancy or severely immunocompromised states

Risk Factors

• Unprotected sexual activity
• Immunocompromised states: advanced age, malignancy, AIDS, diabetes
• Atopic eczema, especially in children
• Occupational exposure (herpetic whitlow in dental professionals)
• High-contact sports (herpes gladiatorum)
• Vertical transmission to the neonate; greatest risk during primary genital infection of the mother

General Prevention

• Avoid contact of active lesions.
• Hand hygiene
• Avoid kissing, sharing beverages, sharing utensils, and sharing toothbrushes when lesions present.
• Genital herpes: Avoid sexual contact if active lesions, but consistent barrier protection use is advised with known limitations; antiviral therapy to reduce viral shedding
• Adult male circumcision reduces transmission to partners.

Commonly Associated Conditions

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