eMedicine Specialties > Emergency Medicine > Infectious Diseases

Herpes Simplex

Author: Rahul Sharma, MD, MBA, Instructor in Medicine, Weill Medical College of Cornell University; Consulting Staff, Department of Emergency Medicine, New York Presbyterian Hospital-Weill Cornell Medical Center
Coauthor(s): Lawrence C Brilliant, MD, Clinical Assistant Professor, Department of Primary Care and Community Services, Hahnemann University; Attending Physician, Department of Emergency Medicine, Doylestown Hospital
Contributor Information and Disclosures

Updated: Sep 4, 2008

Introduction

Background

The herpes simplex viruses comprise 2 distinct types of DNA viruses, HSV-1 and HSV-2. HSV-1 causes oral lesions in approximately 80% of cases and genital lesions in 20% of cases. In adolescents, as many as 30-40% of genital herpes is caused by HSV-1, as this proportion is thought to be increasing in the developed world. The reverse is true for HSV-2, which causes genital lesions in 80% and oral lesions in 20%. About 80% of the general adult population has serologic infection with HSV-1 with only about 30% of these individuals having clinically significant outbreaks. Approximately 20% of the adult population in the United States is seropositive for HSV-2. The indirect and direct costs of incident HSV genital infection in the United States are presently approximately $1.8 billion and expected to be greater than $2.7 billion by the year 2015. Herpes viruses cause a wide range of diseases, including the following:

• Gingivostomatitis
• Keratoconjunctivitis
• Encephalitis
• Genital disease
• Newborn infection

Primary infection

Primary infections usually are mild and, in many cases, asymptomatic. Patients who are immunocompromised may develop severe infections involving multiple organ systems. Immunocompetent individuals also may have severe primary infections.

Latency and recurrence

After the patient begins to produce antibodies, the infection becomes latent in the sensory ganglia. HSV-1 infection remains latent in the trigeminal ganglia and HSV-2 in the sacral ganglia. The viruses become reactivated secondary to certain stimuli, including fever, physical or emotional stress, ultraviolet light exposure, and axonal injury.

Recurrent infections tend to be less severe because of existing cellular and humoral immunity from prior exposures. Infection by HSV requires a break in the skin's barrier; intact skin is resistant to the virus.

For a related CME/CE activity, see Management of Herpes Simplex Infections Reviewed.

Pathophysiology

HSV-1 infections are spread via respiratory droplets or direct exposure to infected saliva. HSV-2 usually is transmitted via genital contact. The contact must involve mucous membranes or open or damaged skin.

Herpes viruses cause cytolytic infections; therefore, pathologic changes are due to cell necrosis as well as inflammatory changes. Fluid accumulates between the dermis and the epidermal skin layers, causing vesicle formation. The fluid then is absorbed, scabs are formed, and healing is completed without evidence of scarring. Shallow ulcers form after the vesicles rupture on mucous membranes.

The virus travels from the site of infection in the skin or mucosa to the sensory dorsal root and remains latent until a recurrent outbreak. Outbreaks are usually due to some sort of stress including ultraviolet radiation, trauma, emotional or psychological stress, or immunosuppression.

Frequency

United States

Approximately 80% of adults have antibodies to HSV-1, whereas antibodies to HSV-2 are found in approximately 20% of the population.

• The incidence of genital herpes has been estimated to be 500,000-1,000,000 cases per year with a prevalence of 40-60 million affected individuals.
• In sexually transmitted disease (STD) clinics, HSV-2 seropositivity approaches 40-50%.
• Encephalitis develops in 1 per 250,000-500,000 patients per year.
• Neonatal HSV develops in 1 per 2,000-10,000 live births per year. Approximately 70% of cases of neonatal HSV occur when the mother is asymptomatically shedding virus near time of delivery. The risk of neonatal transmission is increased if vaginal delivery occurs during acute maternal infection.
• Approximately 90% of HIV-positive individuals are seropositive for HSV-1, and about 77% of HIV-positive individuals are seropositive for HSV-2.

International

Greater than one third the world's population has recurrent clinical HSV infections. Reportedly, 13-40% of the world's population is seropositive for HSV-2 and 56-85% is seropositive for HSV-1, varying by country.

Mortality/Morbidity

Most patients with herpetic infection experience short-term local pain and irritation, with mild constitutional symptoms.

• Infection occasionally may become life threatening.
• Immunocompromised patients are at increased risk of developing severe HSV infections.
• HSV-1 is a common cause of fatal encephalitis in the US, with a mortality rate  60-80%. Fewer than 10% of patients are left without significant neurologic sequelae.
• Keratoconjunctivitis may be caused by HSV-1. It is second only to trauma as a cause of corneal blindness in the US.

Race

HSV-2 antibodies are present in approximately 20% of Caucasian adults and 65% of African American adults. Some experts consider nonwhite race as a risk factor to contract genital HSV-2.

Sex

Men are 20% more likely to develop recurrences of HSV-2 than are women.

Age

• Highest incidence of HSV-1 occurs in children aged 6 months to 3 years.
• HSV-2 most commonly occurs in those aged 18-25 years.

Clinical

History

The typical incubation period from exposure to development of symptoms is 4 days but can range from 1-26 days. Prodromal symptoms of local pain, tingling, itching, and burning often precede development of the rash. Constitutional symptoms of fever, fatigue, myalgias, and headache often accompany the primary HSV infection.

Herpetic lesions usually begin as clusters of small bumps, then blisters, followed by open sores or ulcers. Lesions coalesce and usually heal over several weeks.

Local pain is a prominent and common complaint. Patients with genital herpes may also complain of pain in the groin area secondary to local adenopathy. Women often present with complaints of genital swelling, discharge, and dysuria.

• Many primary infections are asymptomatic. Up to 80% of women with HSV-2 antibodies have no clinical history of infection. However, when primary infections are symptomatic, they are usually more severe than recurrent infections.
• Recurrent lesions are common.
• Patients may give a history that includes the following:
  • Occupational exposure
    • Herpetic whitlow, found in health care workers (especially medical or dental)
    • Herpes gladiatorum on bodies of wrestlers
  • Previous history of herpetic diseases
  • Apparently undiagnosed episodes
• Immune status
  • HIV
  • Malnourishment
  • Hematological malignancies
  • Bone marrow
  • Renal transplant
  • Cardiac transplant
• Neurologic symptoms
  • Headache
  • Confusion
  • Fever
• Lesions
  • Location varies
  • May be very painful
  • Tenesmus, itching with anal/perianal lesions
  • Dysuria with genital lesions
  • Sore throat with oral lesions
• Constitutional symptoms (usually present with development of herpes lesions)
  • Anorexia
  • General malaise
  • Fever
  • Headache
  • Myalgias
• Prodromal symptoms (present in advance of herpes lesions)
  • Burning
  • Itching
  • Tingling
  • Pain

Physical

Physical examination findings of HSV vary depending on location of the lesions.

• General findings
  • Lesions usually are vesicular or ulcerative on an erythematous base (see Media file 1).
  • Lesions coalesce and then heal over the next several weeks.
  • Tender bilateral lymphadenopathy occurs with genital lesions.
• Skin infections (HSV-1 or HSV-2)
  • Herpetic whitlow or paronychia on the fingers of health care workers (not to be confused with abscess). This is usually is due to infection with HSV-1, but HSV-2 infections may be seen with digital-genital contact.
  • Herpes gladiatorum on the bodies of wrestlers and other sports that involve close physical contact. It has been estimated that in Division I National Collegiate Athletic Association (NCAA) wrestling, the incidence of herpes gladiatorum can be as high as 20-40%.
• Oropharyngeal disease
  • Gingivostomatitis (herpes labialis on the lips; see Media file 2)
  • Submandibular lymphadenopathy
  • Fever
• Genital herpes
  • Painful vesicular or ulcerative lesions may appear similar to chancroid or syphilis (see Media file 3)
  • Inguinal lymphadenopathy
  • Genital lesions, especially urethral lesions, may cause transient urinary retention in women
• Keratoconjunctivitis
  • Dendritic keratitis found with slit lamp (see Media file 5)
  • Corneal ulcers
  • Vesicles on eyelids
• Neurologic
  • New psychiatric symptoms (indicative of encephalitis)
    • Confusion
    • Seizures
    • Meningeal signs - Recurrent lymphocytic meningitis (benign form of meningitis/encephalitis that may occur during primary HSV-2 infection)
  • Bell palsy (possible relationship with HSV-1)
• Anal/perianal involvement
  • Discharge
  • Vesicles
  • Ulcerations
  • Inguinal adenopathy

Causes

• HSV-1 - Transmitted through direct contact with infected saliva or direct contact with contaminated utensils
• HSV-2 - Usually acquired as an STD
• Maternal-fetal transmission
• Recurrent disease (reactivation) due to certain stimuli
  • Fever
  • Physical or emotional stress
  • Ultraviolet light exposure
  • Axonal injury

• Search for CME/CE on This Topic »

• Herpes Simplex (Ophthalmology)
• Keratitis, Herpes Simplex (Ophthalmology)
• Herpes Simplex (Dermatology)
• Herpes Simplex Encephalitis (Emergency Medicine)

• Genital Herpes Symptoms
• Genital Herpes Treatment
• Sexually Transmitted Diseases Center
• Genital Herpes Overview
• Genital Herpes Causes
• Teeth and Mouth Center
• Oral Herpes Overview

• Modified Herpes Virus Shows Promise Against Metastatic Melanoma
• High HSV-2 Rate Among HIV-Negative Brazilian Men Tied to Specific Risk Factors
• HSV-1 Pneumonitis May Be Tied to Immunosuppressive Therapy

• Understanding Herpes Simplex Virus: Transmission, Diagnosis, and Considerations in Pregnancy Management
• A Nurse Practitioner's Guide to the Management of Herpes Simplex Virus-1 in Children
• A Nurse Practitioner's Guide to the Management of Herpes Simplex Virus-1 in Children

• Genital Herpes