Genital warts HPV

Genital warts are caused by the human papilloma virus (HPV). There are over 200 subtypes of the virus of which over 25 cause genital infection.

HPV infections of the genital epithelium are thought to be sexually transmitted and are classified as oncogenic (cancer forming or high-risk) (commonly caused by types 16 and 18) and non-oncogenic (low-risk) (commonly caused by types 6 and 11). Infection with the low-risk types may be associated with the formation of genital warts.

Cervical cancer is now known to be caused by oncogenic strains of HPV. It is thought that cervical cancer is preceded by the development of high-grade cervical dysplasia, and that cervical cancer can be prevented by removal of these high-grade lesions. People who develop genital warts may acquire an oncogenic strain of HPV at the same time. Low-grade dysplasia may be caused by either an oncogenic or non-oncogenic strain, or both.

The incubation is 2-3 months although it can range from 1-20 months. The period of communicability is probably at least as long as visible lesions persist. Contact infectivity is high if lesions are present. The school-based quadrivalent HPV vaccination program has been successful in preventing warts in young people.

The majority of newly acquired HPV infections appear to be subclinical and asymptomatic. Clinically visible manifestations of HPV include warts that may be condylomatous, papular, flat or keratotic in appearance. Since the near eradication of genital warts with vaccination, care must be taken not to confuse the infection with molluscum contagiosum. 

STI Atlas (external site)

Essentially, diagnosis of warts is clinical. Tests to detect the high-risk viruses are now available. HPV DNA testing of the cervix, with liquid based cytology should be performed at the time of genital wart diagnosis. Acetic acid testing, in an attempt to demonstrate areas of external genital HPV infection, is not reliable.

Treatment of genital warts is encouraged as they are highly infectious. In addition, if left untreated, the warts may enlarge. However, recurrence is common. Up to 50 per cent of cases have recurrence within the first 6 months following treatment. First line therapy is usually with patient self-applied podophyllotoxin or provider-applied cryotherapy. Advise patients not to shave the pubic area as this spreads the infection.

• Apply podophyllotoxin paint (0.5 per cent, 3.5 mL) (not on PBS) twice daily for three days, and then do not treat for four days. Continue the seven-day cycle for up to four weeks. Some patients may not be able to tolerate this intensity of treatment and reduced frequency is required.
• Apply podophyllotoxin cream (0.15 per cent) topically twice daily for three days, and then do not treat for four days. Continue the seven-day cycle for up to four weeks.
• Cryotherapy: apply liquid nitrogen to visible warts weekly until resolution occurs.
• Surgical ablative therapy may be indicated for extensive lesions. It is useful for single large warts and requires local anaesthesia. Care should be taken to ensure the warts are not condylomata lata of secondary syphilis or donovanosis where, in both cases, antibiotic therapy is the appropriate treatment.
• Apply imiquimod 5 per cent cream topically, 3 times a week for up to 16 weeks (not on PBS).
• Biopsy of atypical or longstanding lesions is recommended to exclude dysplasia, especially in HIV-infected individuals.
• Cervical warts should always be referred to sexual health physicians or gynaecologists for further investigation.
• Quadrivalent vaccination of adolescents is funded by the National Immunisation Program and delivered in high schools. 

Pregnancy

• Surgical ablative therapy
• Liquid nitrogen.
• Medicines in pregnancy.

Precaution

Podophyllotoxin and imiquimod should not be used in pregnancy or breastfeeding.

Related links

• Genital warts (Healthy WA)

Partners should be provided with information about viral shedding and transmission. Viral shedding occurs maximally during the first few days of clinical lesions. However viral shedding and possible transmission can occur at times when there are no clinical signs.

Provide advice on appropriate safe sex practices. 

As determined by the individual case

This is not a notifiable disease.

Always test for other STIs.

If a child is diagnosed with an STI, issues of sexual abuse and/or sexual assault should be considered.