Sexually Transmitted Infections: Herpes

Introduction

• Description: Infection by the herpes simplex virus (HSV) results in recurrent symptoms that range from uncomfortable to disabling. There is a particular risk to neonates when herpes infection occurs during pregnancy.

• Prevalence: Most common cause of genital ulcers. 45–50 million recurrent cases; 1.6 million new cases per year; one in four women have been infected. Roughly 12%–21% of individuals 14–49 years.

• Predominant Age: 15–30 years (85%).

• Genetics: No genetic pattern.

Etiology and Pathogenesis

• Causes: Approximately 80% of genital herpes infections are caused by HSV type 2, with the remaining 20% caused by the HSV type 1 virus, though this percentage is rising. (The type is differentiated based on the glycoproteins in the lipid bilayer envelope.) Up to 50% of first-episode cases of genital herpes are caused by HSV-1. Exposure to type 1 virus often happens in childhood and causes oral “cold sores.” Previous infection with type 1 virus appears to provide some immunity to type 2 infections. The incubation period from infection to symptoms is approximately 6 days (range, 2–12 days), with first episodes lasting from 10 to 12 days. The majority of patients with symptomatic, first-episode genital HSV-2 infection subsequently have recurrent episodes. Recurrences are less frequent after initial genital HSV-1 infection.

• Risk Factors: Approximately 75% of sexual partners of infected individuals contract the disease if intercourse occurs during viral shedding. Patients are infectious during the period from first prodrome through crusting of the lesions. Viral shedding may also occur asymptomatically. Persons unaware that they have the infection or who are asymptomatic when transmission occurs transmit the majority of genital herpes infections. Nonsexual transmission has not been documented.

Signs and Symptoms

• Prodromal phase—mild paresthesia and burning (beginning approximately 2–5 days after infection)

• Progresses to very painful vesicular and ulcerated lesions, 3–7 days after exposure (may prompt hospitalization in up to 10% of patients)

• Dysuria caused by vulvar lesions, urethral and bladder involvement, or autonomic dysfunction (may lead to urinary retention)

• Malaise, low-grade fever, and inguinal adenopathy (40%)

• Systemic symptoms, including aseptic meningitis, fever, headache, and meningismus, can be found in 70% of patients at 5–7 days after the appearance of genital lesions in primary infections.

Diagnostic Approach