Genital warts are caused by the human papilloma virus (HPV), and resemble warts found on other parts of the body. Human papilloma virus (HPV) types 6,11,16,18 commonly cause anogenital infection, whereas types 1,2,3,4 and 10 cause skin warts. Warts usually appear 2 to 8 months after the infection has been acquired, but may take longer, even years, to appear. Asymptomatic infection is also common.
It is important to realise that many people can be infected with the genital wart virus but show no obvious lumpy warts. Individuals infected with the virus, even without the lesions, can infect sexual partners. Some women have no evidence of genital wart virus, except on their Pap smear. Unfortunately, there is no comparable test available for men to ascertain the presence of wart virus infection when there are no lesions.
Because genital warts is not a notifiable disease, no direct statistics are available on its prevalence in Australia. However, in the United Kingdom and many parts of the world, the incidence of genital warts has doubled over the last 10 years.
Genital warts are the most common STD in South Australia. They were present in 13-18% of clients with STDs diagnosed at Clinic 275 between 1988 and 1995.
The warts have a variable morphology, being flat, small and resembling skin warts on cold, dry areas whilst often large and filiform in warm moist areas. Sub-clinical wart virus infection can only be detected on colposcopy.
Males: Condylomata accuminata are typically located around the coronal sulcus, on the glans and the frenulum, at the meatus and sometimes on the shaft and surrounding skin. The rectum, anal canal and perianal areas can also be involved, particularly in homosexual men (but heterosexual men can also be affected).
Warts are rarely found on the scrotum and urethra. Occasionally rectal and genital warts can undergo malignant changes.
Females: The vulva is the commonest site for genital warts in females, especially at the introitus and on the labia. The perineum, perianal region, vagina and cervix can also be involved.
Infants: The virus can be vertically transmitted (from mother to child) during parturition, producing laryngeal papillomata in the newborn.
In women, genital warts have been linked to abnormal changes in cervical cells that can lead to cancer, and are thought to be a co-factor in the development of cervical cancer. This link is not conclusive and has been the subject of much debate. Women who have the wart virus and who smoke are known to have a much higher risk of developing cervical cancer.
Genital warts often spread and enlarge in pregnancy, and may complicate labour by blocking the birth canal or by bleeding.
In men there is a slight risk that untreated warts could develop into cancer of the penis.
It is important that individuals have a check-up if they suspect that they may have genital warts. A doctor will examine the genitals and in some cases my use a diluted acetic acid that turns the warty areas white.
Diagnosis is based on the appearance of the warts which should be differentiated from:
- condylomata lata of secondary syphilis – broad, flat and moist;
- genital molluscum contagiosum – central dimple or umbilication;
- penile papules – small, pearly and arranged in rows (around coronal sulcus);
- vulval skin tags – long and smooth; and
- carcinoma – hard, may be ulcerated.
It is important that women have a Pap smear to check if there is evidence of cervical infection or atypical cells.
Treatment may be prolonged and involves the following important general principles:
- ensure that the affected parts are kept cool and dry;
- investigate and treat women with associated vaginal discharge;
- Papanicolaou smear follow-up is necessary as some HPV genotypes are associated with carcinoma of the cervix; if HPV is detected on the cervix colposcopy may be advisable.
Cryotherapy (preferably with liquid nitrogen) is the preferred treatment. Response to therapy, followed by further treatment if necessary, is assessed once or twice weekly.
When cryotherapy is not available podophyllin in concentrations of 10-50 percent dissolved in spirit or other solvents can be used. The podophyllin should be carefully washed away by the patient after 2-4 hours. If the response is unsatisfactory, the concentration and duration of application would be increased. Podophyllin should NOT be given to patients for self application and should NOT be used in pregnancy, on urethral or cervical warts.
If repeated applications of podophyllin do not clear the condition, trichloroacetic acid or electrocautery (under general anaesthesia if there is an extensive crop of warts), or laser therapy should be tried. In a few patients treatment is ineffective, but the warts eventually disappear.
Genital warts are sexually transmitted and spread most readily in moist areas such as beneath the foreskin of the penis of an uncircumcised man, around the vulva, or around the anus. Warts are spread by genital-to-genital contact, and not by other practices such as oral sex or mutual masturbation.
The genital wart virus continues to live in the body even when no warts are visible, and transmission may occur from “viral shedding” when no obvious warts are present. When warts occur, they may take months to develop after the infection has been acquired
Transmission to infants at birth can occur, and may be reduced by effective treatment of warts in pregnancy – preferably using cryotherapy.
- The use of condoms during vaginal and anal intercourse reduces the risk of genital warts, but only protects those areas in contact with the condom.
- Practices other than intercourse carry less risk of transmitting the virus.
- Regular Pap smears will detect the wart virus on the cervix, and early treatment will substantially reduce the risk of further cervical cell changes and cancer.