INTRODUCTION – AGENTS
Sexually transmitted infections can be divided into those that cause genital ulcers and those that do not. In North America, ulcerative sexually transmitted diseases are most commonly caused by herpes genitalis, syphilis, and, occasionally, chancroid; much rarer causes include lymphogranuloma venereum and granuloma inguinale. Definitive diagnostic tests often are not available in the acute care setting, and empiric treatment with close follow-up is often the best approach.
Genital herpes infection is caused by herpes simplex virus (HSV) types 1 and 2. This is by far the most common cause of ulcerating genital disease in North America: More than 50 million persons in the United States have the disease. Most U.S. cases are caused by HSV-2.
Herpes genitalis can present with a broad range of symptoms. Serologic testing suggests that many infected patients are asymptomatic or have minimal symptoms. Those with an initial genital infection caused by HSV-1 tend to have milder symptoms than those infected with HSV-2. In addition, patients who already have antibodies to HSV-1 (e.g., those with a history of fever blisters) often have milder symptoms with initial HSV-2 genital infection. Symptomatic patients with genital infection caused by HSV-2 who have no prior HSV antibodies tend to present with the most severe disease. In all cases of genital herpes, recurrences may occur and are more common in patients infected with HSV-2.