Herpes Simplex Infections

Key Features

Essentials of Diagnosis

• Grouped vesicles on an erythematous base, typically in or around the mouth or genitals

• Tender regional adenopathy is common with primary infection

• Fever and malaise with primary infection

• Recurrent episodes in many patients

General Considerations

• There are two types of herpes simplex virus (HSV)

• Type 1 (HSV-1)

  • Causes most cases of oral, skin, and cerebral disease in older children

  • Latent infection is routinely established in sensory ganglia during primary infection

  • Recurrences may be spontaneous or induced by external events (eg, fever, menstruation, or sunlight) or immunosuppression

  • Transmission is by direct contact with infected secretions

  • Primary infection is subclinical in 80% of cases and causes gingivostomatitis or genital disease in the remainder

• Type 2 (HSV-2)

  • Transmitted sexually

  • Produces mild, nonspecific symptoms

  • Recurrent episodes are due to reactivation of latent HSV

Clinical Findings

• Gingivostomatitis

  • High fever, irritability, and drooling occur in infants

  • Multiple oral ulcers are seen on the tongue and on the buccal and gingival mucosa, occasionally extending to the pharynx

  • Pharyngeal ulcers may predominate in older children and adolescents

  • Diffusely swollen red gums that are friable and bleed easily are typical

  • Cervical nodes are swollen and tender

  • Duration is 7–14 days

• Vulvovaginitis or urethritis

  • Vesicles or painful ulcers on the vulva, vagina, or penis and tender adenopathy are typical

  • Systemic symptoms (fever, flu-like illness, myalgia) are common with the initial episode

  • Painful urination is frequent, especially in females

  • Primary infection lasts 10–14 days before healing

• Cutaneous infections

  • Direct inoculation onto cuts or abrasions may produce localized vesicles or ulcers

  • A deep HSV infection on the finger (called herpetic whitlow) may be mistaken for a bacterial felon or paronychia

• Recurrent mucocutaneous infection

  • Recurrent oral shedding is asymptomatic

  • Perioral recurrences often begin with a prodrome of tingling or burning limited to the vermillion border, followed by vesiculation, scabbing, and crusting around the lips over 3–5 days

  • Recurrent intraoral lesions are rare

  • Fever, adenopathy, and other symptoms are absent

• Keratoconjunctivitis

  • Produces photophobia, pain, and conjunctival irritation

  • Dendritic corneal ulcers may be demonstrable with fluorescein staining

  • Stromal invasion may occur

• Encephalitis

  • Unusual in infants outside the neonatal period

  • In older children, can follow a primary infection but usually represents reactivation of latent virus

  • Sudden onset is associated with fever, headache, behavioral changes, and focal neurologic deficits and/or focal seizures

• Neonatal infections

  • May be acquired by ascending spread prior to delivery (< 5% of cases)

  • However, occurs most often at the time of vaginal delivery from a mother with genital infection

  • Some infants (45%) have infection limited to the skin, eye, or mouth

  • Other infants are acutely ill, presenting with jaundice, shock, bleeding, or respiratory distress (20%)

  • Some infected infants exhibit only neurologic symptoms at 2–3 weeks after delivery: apnea, lethargy, fever, poor feeding, or persistent seizures

Diagnosis

Laboratory Findings