Genitourinary Skin and Mucous Membrane Infections and Inguinal Lymphadenopathy

Etiologic Agents

The most common infectious causes of GUD are herpes simplex viruses (i.e., HSV-2 and HSV-1) and Treponema pallidum (i.e., syphilis). Although both are STIs, HSV-1 and HSV-2 also can be spread by nonsexual transmission or from autoinoculation. ^, Other STIs that cause GUD include Haemophilus ducreyi (i.e., chancroid); Chlamydia trachomatis serovars L1, L2, and L3 (i.e., lymphogranuloma venereum [LGV]); and Klebsiella granulomatis (i.e., donovanosis or granuloma inguinale). With any GUD, regional lymph nodes can become involved and lead to femoral or inguinal adenopathy or ulceration. Infrequently, scabies and pubic lice can cause GUD.

Non-STI infectious GUD causes include varicella-zoster and Epstein-Barr virus infections, tuberculosis, HIV/AIDS, leishmaniasis, secondary bacterial infections, pyoderma, and infections with Candida species , Capnocytophaga species, Histoplasma capsulatum, Francisella tularensis , Yersinia enterocolitica, or Entamoeba histolytica . GUD also can be associated with noninfectious conditions, including fixed drug eruptions, pyoderma gangrenosum, psoriasis, Behçet syndrome, lichen planus, malignancies, aphthae, Lipschütz vulvar ulcers, and Crohn’s disease. ^,

Epidemiology of Genital Ulcer Disease Caused by Sexually Transmitted Infections

In the US, most young, sexually active people with genital, anal, or perianal ulcers have genital herpes or syphilis. Their frequencies vary by geographic area and population. However, genital herpes is more prevalent and is the leading cause of GUD worldwide. ^,

HSV infections are lifelong, often asymptomatic, and cause intermittent viral shedding in the genital tract. Most HSV infections are transmitted by people unaware that they are infected. In 2018, an estimated 1.3 million HSV-2 infections occurred among US people between the ages of 18 and 24 years. The majority of cases of recurrent genital herpes are caused by HSV-2 and 11.9% of persons 14–49 years of age are estimated to be infected in the US. HSV-1, which typically causes orolabial herpes, is increasingly the cause of genital herpes. The growing numbers of adolescents who lack HSV-1 antibodies at sexual debut likely contributes to the percentage of genital herpes (50%–80%) due to HSV-1 in some populations of young women.

Syphilis remains a major US health problem, particularly among men who have sex with men (MSM). ^, Primary and secondary syphilis rates have increased over the past decade, with 53% of cases occurring among MSM in 2018. Between 2014 and 2018, the primary and secondary syphilis rate among women increased 173%. Of the 7758 primary and secondary syphilis cases among US persons between the ages of 15 and 24 years in 2018, 80% occurred in males.

The US prevalence of chancroid has declined with only 3 cases reported in 2018, and it has declined in countries where it was previously endemic. ^, However, due to the difficulty in detecting H. ducreyi in the laboratory, chancroid may be underreported. Chancroid infections in the US are usually associated with sporadic outbreaks.

LGV is endemic in parts of Africa, Southeast Asia, Latin America, and the Caribbean. Since 2003, LGV proctocolitis has also been reported among MSM in the US, Europe, and Australia; LGV proctocolitis outbreaks have been reported among MSM with high rates of HIV co-infection. ^, Granuloma inguinale occurs rarely in the US but sporadic cases have been described in parts of India, South Africa, and South America. ^{, ,}

Clinical Manifestations and Differential Diagnosis

Determining the cause of GUD is challenging based solely on clinical presentation. GUD in children and adolescents requires a thorough history and physical examination to exclude underlying systemic conditions, recent illnesses, or medications, and to identify associated factors such as sexual activity or abuse. Frequently, specialized testing is required to establish the cause.

Classic clinical features of GUD are described in Table 50.1 . In practice, the etiologic diagnosis may be indistinguishable because of coexisting infections, atypical presentations, medication effects, or immunocompromising conditions. Careful examination of the entire genital region, including the perineum and anus, and areas of lymphadenopathy which is facilitated by a good light source and magnifying lens, may improve clinical assessments and guide the choice of diagnostic tests. Anoscopic examinations can identify asymptomatic anorectal manifestations potentially overlooked by the patient and clinician and improve GUD diagnosis and treatment.