Causes of Genital Warts

Dr Kathryn Basford

Medically reviewed by

Dr Kathryn Basford

Last reviewed: 28 Feb 2019

How are genital warts transmitted?

Woman with short hair sat on couch at home looking at mobile phone researching causes of genital warts

Key takeaways

  • Genital warts are caused by HPV (the human papilloma virus), which is a common STI in people under 30 years old

  • Not everyone infected with HPV will develop genital warts

  • To prevent genital warts you should use condoms and avoid unprotected genital-to-genital contact without penetration

  • Some strains of HPV can cause cervical cancer. However, the strains of HPV which cause genital warts do not commonly cause cervical or penile cancer

Genital warts are caused by HPV (the human papilloma virus). HPV is a sexually transmitted infection and is most common in people aged under 30. It's estimated that half of all sexually active people are infected with HPV at some point.

Not everyone infected with HPV will develop genital warts. This's because the body often contains the virus before it causes any symptoms.

People with a weak immune system are more vulnerable and therefore more likely to develop warts. Suffering from another disease as well as an unhealthy lifestyle and diet can contribute to weakening your immune system.

What causes genital warts?

As with any other sexually transmitted infection (STI), HPV (the human papilloma virus) is transmitted via sexual intercourse, including anal and oral sex. It can take several months for genital warts to appear after you have sex with an infected person.

But, you can also be infected through genital contact and in rare cases, babies have been found to catch the virus during childbirth.

About HPV

Out of the over 100 different strains of HPV, about 30 to 40 are transmitted sexually. Yet, only a few of these strains are responsible for causing genital warts.

Other strains of the virus are associated with warts elsewhere on the body. Certain high-risk strains of HPV, different to the ones that cause genital warts, can cause cervical, penile, anal, and throat cancer.

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Genital warts risk factors

People aged between 20 and 24 have the highest rates of genital warts. Girls aged 15 to 19 used to have higher rates, but since the HPV vaccine programme was started, this has reduced.

Risk factors include:

  • previous infection with another STI (it increases the risk of further STI infection)
  • becoming sexually active at a young age (the immune system might not be mature enough to fight the virus on its own)
  • tobacco, alcohol and stress which can trigger recurrent eruptions or complications from an HPV infection

To prevent genital warts you should:

  • use condoms, especially when frequently changing sexual partners (i.e. more than two per year)
  • avoid unprotected genital-to-genital contact without penetration

If you experience a sudden and severe outbreak of genital warts, go to your local health clinic or doctor to get tested. A severe and rapid growth and spread of genital warts can be a sign of a problem with your immune system (and possibly an HIV infection).

Always bear in mind that condoms do not provide 100% protection as warts can be located in areas not covered by condoms. The infection can also be passed on by any skin to skin contact even without penetration.

Genital warts statistics

There were over 59,119 new cases diagnosed at sexual health services in England in 2017. But this number was a 7% drop compared to 2016.

This fall in cases of genital warts is mostly because more young women are being given the HPV vaccine at 12 or 13 years old.

How dangerous is HPV?

Some strains of HPV can cause cervical cancer. The strains of HPV which cause genital warts, however, do not cause cervical or penile cancer.

Women should make sure they’re up to date with their smear tests. The NHS has a screening programme that invites all women between the ages of 25 and 64 for regular smear tests. If you’re not sure when your next one should be, you can check this with your GP.

Medically reviewed by:
Dr Kathryn Basford

Dr Kathryn Basford is a qualified GP who works as a GP in London, as well as with ZAVA. She graduated from the University of Manchester and completed her GP training through Whipps Cross Hospital in London.

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Last reviewed: 28 Feb 2019

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When you get an outbreak of genital warts, you can treat them with topical gels and creams. ZAVA offers a variety of these creams and gels through a discreet, convenient service.

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