Diagnosis

Herpes simplex

Etiology

Cause [ivs]

• Type 1: traditionally associated with orofacial disease

• Type 2: traditionally associated with genital disease

• Lesion location is not necessarily indicative of viral type

Pathogenesis [8nw][tgw][gkn]

1. Viral spread: saliva, shared drinkware/cosmetics/razor, or mouth to mouth contact

2. The virus replicate at the site of infection (mucoepithelial tissue) and later travel retrograde along an axon to the dorsal root ganglia

3. Neurovirulence: the capacity to invade and replicate in the nervous system.

4. Latency is established in nerve ganglia (trigeminal ganglia, sacral nerve root ganglia)

5. Reactivation and replication of latent HSV induced by:

   • Fever

   • Trauma

   • Emotional stress

   • Sunlight

   • Menstruation

6. Dissemination of herpes simplex infection can occur in people with impaired T-cell immunity, such as in organ transplant recipients and in individuals with AIDS

7. Clinical presentation

   • Acute gingivostomatitis/pharyngotonsillitis

   • Recurrent mucocutaneous herpes

   • Herpes labialis

   • Primary genital herpes

   • Recurrent genital herpes

   • Subclinical genital herpes

Complication [ivs][e1v][gkn]

• Perinatal infection:

  • Genital infection at the time of birth --> risk for neonatal herpes, a devastating disease with high mortality and a high rate of permanent neurologic impairment

  • Both HSV-1 and HSV-2 can cause neonatal herpes infection

  • Incidence ~2-16 per 100,000

  • Cesarean section decreases but does not entirely prevent neonate HSV-infection

• Encephalitis

• Ocular HSV infection: 10-20 per 100,000

• Acute retinal necrosis

• Severe infection in the immunocompromised host

Epidemiology

Prevalence per 100.000 [8nw][cpp][cew]

Incidence per 100.000 [8nw][cpp][cew]

Approach

• Tissue culture: A direct swab of vesicular lesions

• Immunofluorescent staining of the tissue culture

• PCR

• HSV serotyping

• Antibody testing

• Lumbar puncture

• CT caput

• MR caput

• Brain biopsy (viral encephalitis)

Treatment

1. Antiviral treatment: Start antiviral therapy at the first symptom [8nw][tgw]

   • Oral antiviral treatment: acyclovir/famciclovir/valacyclovir

     • Orolabial herpes: Valacyclovir 2 grams twice daily for one day

     • Chronic suppression of immunocompromised: Valacyclovir 1 gram/day

     • Eczema herpeticum: Valacyclovir 1 gram twice a day for 10-14 days

   • IV acyclovir

     • Encephalitis, neonatal disease, severe infection in immunocompromised patients, occasional cases of severe orolabial or genital disease

2. Pregnant women with symptomatic genital herpes --> consider antiviral treatment

3. Cesarean delivery if a mother has active lesions during delivery

Differential diagnoses

Aphthous stomatitis, Behcet's disease, Candidiasis, Chancroid, Chickenpox, Cytomegalovirus, Drug eruptions, Erythema multiforme, Erythema toxicum neonatorum, Granuloma inguinale, Hand-Foot-and-Mouth disease, Herpangina, Herpes zoster, Lymphogranuloma venereum, Psoriasis, Sepsis, Stevens-Johnson syndrome, Syphilis