Human papillomavirus (HPV) infects epithelial cells. Most of the > 100 subtypes infect cutaneous epithelium and cause skin warts; some types infect mucosal epithelium and cause anogenital warts. Skin or anogenital warts are diagnosed based on clinical appearance and are usually treated with topical medications or cytodestructive treatments. Genital warts may persist and spread widely in patients with decreased cell-mediated immunity (eg, due to pregnancy or HIV infection). Some types that infect mucosal epithelium can lead to anogenital or oropharyngeal cancer. Pap tests and/or HPV testing is recommended to screen for cervical cancer and anal cancer in high-risk patients. Vaccines are available to protect against many of the HPV strains that can cause genital warts and cancer.
(See also Overview of Sexually Transmitted Infections.)
HPV is the most common sexually transmitted infection (STI). HPV is so common that 80% of sexually active unvaccinated people get the virus at some point in their life (1). In the US, about 14 million people become newly infected with HPV each year; before the HPV vaccine became available, each year roughly 340,000 to 360,000 patients sought care for genital warts caused by HPV.
Most HPV infections clear spontaneously within 1 to 2 years, but some persist.
General reference
1. Centers for Disease Control and Prevention: Human papillomavirus (HPV). Accessed July 6, 2022.
Etiology of HPV Infection
There are > 100 known types of HPV. Some infect cutaneous epithelium and cause common skin warts. Some infect primarily the mucosa of the anogenital region, as well as the oropharyngeal and laryngeal areas.
Important manifestations of anogenital HPV include
Genital warts (condyloma acuminatum)
Intraepithelial neoplasia and carcinoma of the cervix, vulva, vagina, anus, or penis
Laryngeal and oropharyngeal cancers
Bowenoid papulosis
Some data suggest HPV plays a role in the pathogenesis of some bladder cancers.
Condylomata acuminata are benign anogenital warts most often caused by HPV types 6 and 11, as are laryngeal and oropharyngeal warts. Low- and high-grade intraepithelial neoplasia and carcinoma may be caused by HPV.
Virtually all cervical cancer is caused by HPV; about 70% is caused by types 16 and 18, and many of the rest result from types 31, 33, 45. 52, and 58 (1). HPV types that affect mainly the anogenital area can be transmitted to the oropharynx by orogenital contact; type 16 appears responsible for many cases of oropharyngeal cancer. HPV types 16 and 18 can also cause cancer in other areas, including the vulva, vagina, anus, and penis.
Pearls & Pitfalls
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HPV is transmitted from lesions during contact with skin or mucosa. The types that affect the anogenital region are usually transmitted sexually by vaginal or anal intercourse, but digital, oral, and nonpenetrative genital contact may be involved.
Genital warts are more common among immunocompromised patients. Growth rates vary, but pregnancy, immunosuppression, or maceration of the skin may accelerate the growth and spread of warts.
Reference
1. Serrano B, Alemany L, Tous S, et al: Potential impact of a nine-valent vaccine in human papillomavirus related cervical disease. Infect Agent Cancer 7(1):38, 2012. doi:10.1186/1750-9378-7-38
Symptoms and Signs of HPV Infection
Warts caused by HPV appear after an incubation period of 1 to 6 months.
Visible anogenital warts are usually soft, moist, minute pink or gray polyps (raised lesions) that
Enlarge
May become pedunculated
Have rough surfaces
May occur in clusters
The warts are usually asymptomatic, but some patients have itching, burning, or discomfort.
In men, warts occur most commonly under the foreskin, on the coronal sulcus, within the urethral meatus, and on the penile shaft. They may occur around the anus and in the rectum, especially in men who have sex with men.
In women, warts occur most commonly on the vulva, vaginal wall, cervix, and perineum; the urethra and anal region may be affected.
HPV types 16 and 18 usually cause endocervical or anal intraepithelial lesions that are difficult to see and diagnose clinically.
This photo shows small, soft, pink genital warts on the penile shaft.
© Springer Science+Business Media
This photo shows pink and raised genital warts (arrows) at the coronal sulcus of the penis.
© Springer Science+Business Media
This photo shows the typical rough, pedunculated appearance of genital warts on the glans.
© Springer Science+Business Media
Image courtesy of Dr. M.F. Rein via the Public Health Image Library of the Centers for Disease Control and Prevention.
Genital warts on the vulva may be raised and light-colored with an irregular, rough surface.
Image courtesy of Joe Millar via the Public Health Image Library of the Centers for Disease Control and Prevention.
This photo shows small, soft, pink genital warts on the penile shaft.
© Springer Science+Business Media
This photo shows pink and raised genital warts (arrows) at the coronal sulcus of the penis.
© Springer Science+Business Media
This photo shows the typical rough, pedunculated appearance of genital warts on the glans.
© Springer Science+Business Media
Image courtesy of Dr. M.F. Rein via the Public Health Image Library of the Centers for Disease Control and Prevention.
Genital warts on the vulva may be raised and light-colored with an irregular, rough surface.
Image courtesy of Joe Millar via the Public Health Image Library of the Centers for Disease Control and Prevention.
Diagnosis of HPV Infection
Physical examination
HPV testing
Cervical, and sometimes anal, cytology (Pap test)
Sometimes colposcopy, anoscopy, or both
Genital warts are usually diagnosed with gross visual inspection. Their appearance usually differentiates them from condyloma lata of secondary syphilis (which are flat-topped) and from carcinomas. However, serologic tests for syphilis (STS) should be done initially and after 3 months. Biopsies of atypical, bleeding, ulcerated, or persistent warts may be necessary to exclude carcinoma.
Screening for cervical cancer is discussed elsewhere in THE MANUAL.
Nucleic acid amplification tests (NAATs) for oncogenic HPV subtypes are used as part of routine cervical cancer screening in women. Initial tests typical detect any one of 13 common high-risk types. Follow-up HPV genotype tests may be done to detect the most high-risk types, typically 16, 18, or 45. No HPV testing for men is available for clinical use.
Clinicians should check for malignant oral lesions potentially caused by HPV during routine examination of the mouth and oral cavity.
Diagnosis references
1. World Health Organization (WHO): Human papillomavirus (HPV) nucleic acid amplification tests (NAATs) to screen for cervical pre-cancer lesions and prevent cervical cancer; policy brief; 16 March 2022
2. International Agency for Research on Cancer: A practical manual on visual screening for cervical neoplasia; Anatomical and pathological basis of visual inspection with acetic acid (VIA) and with Lugol’s iodine (VILI). IARC Technical Publication No. 41, 2003. ISBN 92 832 2423 X
Treatment of HPV Infection
Cytodestructive therapy or excision (eg, by caustics, cryotherapy, electrocauterization, laser, or surgical excision)
Topical medications (eg, with antimitotics or interferon inducers)
No treatment of anogenital warts is completely satisfactory, and relapses are frequent and require retreatment. In immunocompetent patients, genital warts may resolve without treatment. In immunocompromised patients, warts may be less responsive to treatment.
Because no treatment is clearly more efficacious than others, treatment of anogenital warts should be guided by other considerations, mainly wart size, number, and anatomic site; patient preference; cost of treatment; convenience; adverse effects; and the practitioner's experience (see the Centers for Disease Control and Prevention [CDC] 2021 Sexually Transmitted Infections Treatment Guidelines: Anogenital Warts).
Genital warts may be treated with
Caustics
Topical medications
Cryotherapy
Electrocauterization
Laser
Surgical excision
A local or general anesthetic is used depending on the size and number to be removed. Extensive vulvovaginal warts may require laser ablation. For anal warts, removal with a resectoscope may be the most effective treatment; a general anesthetic is used.
By removing the moist underside of the prepuce, circumcision may prevent recurrences in uncircumcised men.
Current sex partners of people with genital warts should be examined and, if infected, treated.
For intraurethral lesions,
Cervical intraepithelial neoplasia (CIN) is monitored with excisional biopsy.
Vulvar and vaginal intraepithelial neoplasia are treated with surgical excision.
Sex partners of patients with cervical intraepithelial neoplasia or carcinoma and of patients with bowenoid papulosis should be counseled and screened regularly for HPV-related lesions. A similar approach can be used for HPV in the rectum.
Management of cancers caused by HPV is discussed elsewhere in THE MANUAL.
Prevention of HPV Infection
(For more information, see Childhood Vaccination Schedule and Human Papillomavirus Vaccination for Adults: Updated Recommendations of the Advisory Committee on Immunization Practices.)
A 9-valent vaccine and a quadrivalent vaccine protect against the 2 types of HPV (types 6 and 11) that cause > 90% of visible genital warts. These vaccines also protect against the 2 types of HPV (types 16 and 18) that cause most cervical cancers. The 9-valent vaccine also protects against other types of HPV (types 31, 33, 45, 52, and 58) that cause about 15% of cervical cancers. A bivalent vaccine protects against only types 16 and 18.
Only the 9-valent vaccine is available in the US.
The current recommendations from the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control are as follows:
For both females and males up to age 26 years: HPV vaccine is recommended at age 11 or 12 years (can start at age 9 years) and for previously unvaccinated or not adequately vaccinated patients up through age 26 years.
For adults 27 to 45 years: Clinicians should engage in a shared decision-making discussion with patients to determine whether they should be vaccinated.
Because HPV can be transmitted by skin-to-skin contact, condoms do not fully protect against infection.
Key Points
Anogenital warts are caused by human papillomavirus (HPV), most commonly types 6 and 11.
HPV types 16 and 18 cause about 70% of cervical cancers and can cause cancer in other areas, including the vulva, vagina, penis, anus, and oropharynx.
Diagnose warts by inspection; HPV testing is available to screen for cervical cancer.
Treat warts with cytodestructive treatments, topical medications, or surgical excision.
Treat cervical, vaginal, vulvar, or anal intraepithelial neoplasia with ablation or excision or manage with close surveillance.
HPV vaccination is recommended for children and young adults.
More Information
The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
Centers for Disease Control and Prevention: 2021 Sexually Transmitted Infections Treatment Guidelines: Anogenital Warts: A source of clinical guidance emphasizing treatment of STIs and discussing prevention strategies and diagnostic recommendations
