Herpes Simplex
A common infection, herpes simplex virus (HSV) occurs subclinically in about 85% of patients. In the rest, it causes localized lesions. HSV may be latent for years, but after the initial infection, the patient becomes a carrier susceptible to recurrent attacks. The outbreaks may be provoked by fever, menses, stress, heat, cold, lack of sleep, sun exposure, and contact with reactivated disease (for example, by kissing or by sharing cosmetics).
In recurrent infections, the patient usually has no constitutional signs and symptoms.
In recurrent infections, the patient usually has no constitutional signs and symptoms.
Generally not serious in an otherwise healthy adult, HSV infection in an immunocompromised patient, such as one with acquired immunodeficiency syndrome (AIDS), can produce severe illness. In fact, serious HSV infections are a prominent feature of AIDS.
HSV infection occurs worldwide equally in males and females. Lower socioeconomic groups are infected more commonly, probably because of crowded living conditions.
Causes
Herpesvirus hominis, a widespread infectious agent, causes two serologically distinct HSV types. Type I (HSV–1) is transmitted primarily through contact with oral secretions. It mainly affects oral, labial, ocular, or skin tissues. Type 2 (HSV–2), transmitted primarily by contact with genital secretions, mainly affects genital structures. Infection with HSV–1 occurs more frequently and earlier in life than infections with HSV–2. More than 90% of adults have antibodies to HSV–1 by age 40; in lower socioeconomic groups, most persons acquire HSV–1 infection before age 20. Antibodies to HSV–2 aren’t routinely detected before puberty.
Although HSV most commonly occurs in the structures mentioned, it may infect any epithelial tissue. The incubation period varies, depending on the infection site. The average incubation for infection is 1 to 26 days.
Complications
Primary (or initial) HSV infection during pregnancy can lead to abortion, premature labor, microcephaly, and uterine growth retardation. Congenital herpes transmitted during vaginal birth may produce a subclinical neonatal infection or severe infection with seizures, chorioretinitis, skin vesicles, and hepatosplenomegaly.
Pediatric pointerIn infants, HSV–1 can cause life–threatening nonepidemic encephalitis. Primary HSV infection is a leading cause of gingivostomatitis in children ages 1 to 3 years.
Blindness may result from ocular infection. Females with HSV may be at increased risk for cervical cancer. Urethral stricture may result from recurrent genital herpes.
Perianal ulcers, colitis, esophagitis, pneumonitis, and various neurologic disorders, resulting from HSV infection, are serious complications in patients with AIDS and other immunocompromised conditions. Viremia can occur, with multiple organ involvement.
Assessment
In a patient with suspected herpes simplex, the history may reveal oral, vaginal, or anal sexual contact with an infected person or other direct contact with lesions. With recurrent infection, the patient may identify various precipitating factors. (See Detecting herpes simplex, page 398.)
Diagnostic tests
Confirmation of HSV infection requires isolating the virus from local lesions and a histologic biopsy. In primary infection, a rise in antibodies and moderate leukocytosis may support the diagnosis.
