A 16-year-old boy presents with growths in the genital area for about 1 month (Figure 118-1). He has never had a sexually transmitted disease (STD) or vaccination against human papillomavirus (HPV) infection. He has had multiple sexual partners. The patient is told that he has genital warts which are an STD caused by HPV. The treatment options are discussed and he chooses to have cryotherapy with liquid nitrogen. A urine test for gonorrhea and Chlamydia is performed and the patient is tested for syphilis and HIV. Fortunately, all the additional tests are negative. Further patient education is performed and follow-up is arranged.
Condyloma acuminata in 16-year-old circumcised boy not practicing safe sex. He has isolated lesions on the shaft of the penis. He was treated with cryotherapy using liquid nitrogen. (Used with permission from Richard P. Usatine, MD.)
More than 100 types of HPV exist, with more than 40 that can infect the human genital area. Most HPV infections are asymptomatic, unrecognized, or subclinical. Low-risk HPV types (e.g., HPV types 6 and 11) cause genital warts, although coinfection with HPV types associated with squamous intraepithelial neoplasia can occur. Asymptomatic genital HPV infection is common in sexually active persons and usually self-limited.1
Anogenital warts are the most common viral STD in the US. There are approximately 1 million new cases of genital warts per year in the US.2
Most infections are transient and cleared within 2 years.2
Some infections persist and recur and cause much distress for the patients.
Etiology and Pathophysiology
Genital warts are caused by HPV infection in males (Figure 118-1) and females (Figure 118-2). HPV encompasses a family of primarily sexually transmitted double-stranded DNA viruses. The incubation period after exposure ranges from 3 weeks to 8 months.
HPV can be transmitted both sexually and non-sexually.3 Cutaneous HPV types can persist over a long time in healthy skin.4 HPV DNA detection in amniotic fluid, fetal membranes, cord blood and placental trophoblastic cells all suggest some HPV infection may occur in utero (prenatal transmission).3
The first systematic review on vertical transmission of HPV included 2,113 newborns found the pooled mother-to-child HPV transmission was 6.5 percent. Transmission was higher after vaginal delivery than after caesarean section (18.3% vs 8%) (RR = 1.8; 95% CI 1.3–2.4).5
Most of the mucosal HPV infections in infants are incidental, persistent infections in oral and genital mucosa being found in less than 10 and 2 percent respectively.3 Condyloma acuminata in children younger than two to three years of age are more likely the result of maternal-child transmission, but ...