HPV is a non-enveloped, double-stranded, circular DNA virus of the Papillomaviridae family. The virus enters the epithelium through disruption to the skin/mucosa and infects basal stem cells. Its genome contains seven early (E) and two late (L) phase genes required for viral propagation. The viral DNA may remain as an independent episome for a period before integrating into the host’s genome. HPV preferentially integrates at fragile sites in the human DNA where the strand is prone to breakages.
HPV subtypes show a predilection for body sites they most commonly infect, and disease manifestations that result from infection may vary. Over 180 subtypes of HPV have been identified. Cutaneous warts of the hands and feet, such as verruca vulgaris or verruca plantaris, are most commonly caused by HPV subtypes 1, 2, 4, 27, or 57. Most anogenital warts, such as condyloma acuminatum, are caused by HPV subtypes 6 or 11 and termed low-risk HPV; these subtypes also are responsible for juvenile and adult recurrent respiratory papillomatosis. Pre-cancerous and cancerous lesions of the cervix, male and female anogenital areas and oropharyngeal area are most commonly caused by HPV subtypes 16 and 18. However, subtypes 31, 33, 35, 45, 52, and 58 also fall in the high-risk HPV group as they are associated with the development of cervical cancer.
The HPV subtypes which cause cutaneous verrucae are spread by contact between skin with microscopic or macroscopic epidermal damage and a fomite-harboring HPV. The prototypical location for contracting warts of the feet is a locker room.
Both low-risk and high-risk HPV (sometimes referred to as alpha-papillomaviruses) are considered to be sexually transmitted but may be spread by other forms of intimate contact. According to the Center for Disease Control and Prevention (CDC), the most recent studies show the prevalence of genital HPV for adults aged 18 to 59 to be approximately 45.2% in men and 39.9% in women.
E6 and E7 are oncoproteins which inactivate p53 and pRb proteins respectively; these inactivations lead to dysregulation of the cell cycle and neoplastic transformation of affected tissue. The virus remains relatively inactive in early infection but keeps the cell from entering a resting (G0) state. As the infected cells grow and mature, E2 regulates the transition from early- to late-phase genes, and the virus increases production of virions for dispersal. This increase in virion production in HPV-driven lesions typically manifests as hypertrophy of the infected tissue (discrete, thickened lesions, e.g., the common wart) with the potential for atypia and malignant transformation in those lesions infected with high-risk HPV.
Evaluation and treatment of HPV infection vary by body site and disease manifestation. For a more in-depth examination of each disease entity, please visit those specific topics.
Cutaneous warts (verruca vulgaris, verruca plantaris): Ask about potential infectious contacts and hygiene habits (e.g., "Do you wear shower shoes when showering at the gym?" or "Are the lesions painful and/or prone to bleeding?")
Anogenital warts (condyloma acuminatum): Providers should ask about:
Patients with cutaneous, anogenital, and/or oropharyngeal warts may have them excised and submitted for histopathological examination if there is any question as to the diagnosis or concern for dysplasia.
Screening for cervical dysplasia/malignancy is typically accomplished through speculum examination and Pap smear with concurrent or reflex HPV testing, which is an assay test performed on cervical cells to evaluate for the most common HPV subtypes associated with dysplasia. Treatment protocols stratify patients by age, HPV status, and Pap smear results. Depending on treatment stratification, patients with results concerning for intraepithelial squamous or glandular lesions may proceed to colposcopy (a procedure in which the cervix is coated with acetic acid, acetowhite areas are evaluated with a colposcope, and concerning areas are biopsied to examine for histopathologic evidence of dysplasia or malignancy).
Individuals with cutaneous warts have numerous treatment options available including surgical removal, cryotherapy (freezing the infected tissue), irritant or immunomodulating medications, and laser removal. The overarching purpose behind many of these treatments is to manually or chemically irritate the area, thereby invoking a host immune response to assist in clearing the infected tissue.
For the prevention of lower anogenital tract HPV infection by the most common high-risk and low-risk subtypes, the CDC recommends that boys and girls be vaccinated for HPV starting at ages 11 to 12. It is further recommended that women may get vaccinated through the age of 26 and men through the age of 21.
Anogenital and oropharyngeal warts may be treated similarly to cutaneous warts as long as the patient is immunocompetent. Development of HPV-related carcinoma at these sites may require resection, chemotherapy, and/or radiation.
Cervical HPV-driven lesions may regress without any intervention. Young immunocompetent women with dysplasia are usually monitored at shortened intervals through Pap smears, HPV testing, and colposcopic examination. Persistent cervical dysplasia at any age, or high-grade dysplasia in older women, is treated with cryotherapy, loop electrosurgical excision procedure (LEEP), or cold knife cone (CKC) excision. Both of the surgical procedures (LEEP, CKC) involve resection of the cervical os and transformation zone. If the patient progresses to malignancy (e.g., squamous cell carcinoma, endocervical adenocarcinoma), further resection, chemotherapy, and/or radiation may be required.
For a fuller explanation of the disease entities associated with HPV infection, please visit those topics specifically.
HPV is known to cause lesions of the mucous membranes and skin. There are over 100 subtypes of HPV, and some are associated with an increased risk of malignancy. For the most part, HPV is sexually acquired, and one of the best ways to decrease the morbidity of this infection is the education of the patient. Both the nurse and the pharmacist are in a prime position to educate patients about safe sex, use of condoms and avoidance of multiple sex partners. Further, women should be encouraged to undergo the Pap smear to screen for cervical dysplasia and presence of HPV. More important, patients should be told that if they have the presence of genital warts, sexual activity should be avoided until the lesions have been treated or have resolved. The pharmacists should also encourage the patients to be vaccinated against HPV. Finally, patients need to be educated that if they have HPV, they should be screened for other sexually transmitted infections. (Level II)
Once HPV is acquired, recurrences are common. However, for most patients with genital warts, there are treatments. In about 60% of cases, genital warts resolve spontaneously. Irrespective of treatment of genital warts, the risk of cervical cancer is not altered.
The biggest concern with genital warts is the risk of cervical cancer. HPV is also known to be associated with anal and head and neck cancers. Individuals who are immunocompromised are also at risk for developing dysplasia or cancer of the vagina and vulva.